CONTENTS Pere CURR GIS ae Te oO Re Ue POU N CaLC NAY a eel ae eae eae) t Poet ese LUN Dc emcee Lf) Eee} Paes ea etc hl Beeler soir Peg oN Lee 15 PLANETARY GEAR SETS. rst POLAR emcee Lae veo aren een eee Cee COMPLETE HYDRAULIC CIRCUITS . Pee ee EUR aC Thr Sao Tg Eres Da sre Ue oe - aC) OR : = 105, Nae 5 aC I, o> Reena - : sae Lf 101 ee eereRCEeE Pre oa coerce eee eee ereHOW TO USE THIS BOOK LARGE CUTAWAY VIEW HALF PAGE TEXT FOR EASY RANGE REFERENCE CHART (OF TRANSMISSION REFERENCE TO BOTH PAGES (FOLDOUT) PAGE NUMBER — FOR REFERENCE TO FLUID FLOW SCHEMATIC FLUID FLOW SCHEMATIO— FLUID FLOW THROUGH (FOLDOUT) COMPONENTS (FOLDOUT) HALF PAGE TEXT AND LEGEND eae ee ueaes PARTS LIST Figure 1UNDERSTANDING THE GRAPHICS (12-23) SPACER PLATE GASKETS (are 82) Figure 2 The flow of transmission fluid starts in the bottom pan and is drawn through the filter, main case valve body, transmission case and into the oil pump assembly. This is a general route for fluid to flow that is more easily understood by reviewing the illustrations provided in Figure 2. However, fluid may pass between these and other components many times before reaching a valve or applying a clutch. For this reason, the graphics are designed to show the exact location where fluid passes through a component and into other passages for specific gear range operation. To provide a better understanding of fluid flow in the Hydra-matic 4L60-E transmission, the components involved with hydraulic control and fluid flow are illustrated in three major formats. Figure 3 provides an example of these formats which are: + A three dimensional line drawing of the ‘component for easier part identification, + Atwo dimensional line drawing of the component to indicate fluid passages and orifices. A graphic schematic representation that displays valves, checkballs, orifices and so forth, required for the proper function of transmission in a specific gear range. In the schematic drawings, fluid Circuits are represented by straight lines and orifices are represented by indentations ina circuit. All circuits are labeled and calor coded to provide reference points between the schematic drawing and the two dimensional line drawing of the components, Figure 4 (page 7A) provides an illustration of a typical valve, bushing and valve train components. A brief description of valve operation is also provided to support the illustration. Figure 5 (page 7A) provides a color coded chart that references different fluid pressures used to operate the hydraulic control systems. A. brief description of how fluid pressures affect valve operation is also provided.UNDERSTANDING THE GRAPHICS OIL PUMP ASSEMBLY (4) PUMP BODY (200) PUMP COVER (215) ES ‘THREE DIMENSIONAL TWO DIMENSIONAL. CONTROL VALVE BODY ASSEMBLY (60) CASE SIDE i =i = |) =) a at : =| : ar ‘THREE DIMENSIONAL ‘TWO DIMENSIONAL, GRAPHIC SCHEMATIC REPRESENTATION 1-2 ACCUMULATOR COVER (57) CASE SIDE THREE DIMENSIONAL “TWO DIMENSIONAL [GRAPHIC SCHEMATIC REPRESENTATION ‘SPACER Gnaeee | (PLATE Gases, \VALVEBODY SIDE ungesrarcTeD 7) (48) 62) [SPACER PLATE: cASHET, aS GASKET _— = onIFice IN I SPACER I PUTE pleat eee SS) ‘THREE DIMENSIONAL ‘TWO DIMENSIONAL GRAPHIC SCHEMATIC REPRESENTATION Figure 3 FOLDOUT > 7;-HYDRA-MATIC 4L60-E. SPEED SENSOR PARKING PAWL PARKING Lock. "ASSEMBLY ACTUATCR ASSEMBLY MANUAL CONTROL VALVE ‘SHAFT FaureGENERAL DESCRIPTION The Hydra-matic 4L60-E is a fully automatic, four speed, rear wheel drive transmission. It consists prima- rily of a four-element torque converter, two planetary gear sets, various clutches, an oil pump, and a control valve body. The four-element torque converter contains a pump, a turbine, a pressure plate splined to the turbine, and a stator assembly. ‘The torque converter acts as a fluid coupling to transmit power smoothly from the engine to the transmission. It also hydraulically provides addi tional torque multiplication when required. The pressure plate, when applied, provides a mechanical “direct drive” coupling of the engine to the transmission. The two planetary gear sets provide the four forward gear ratios and reverse. Changing of the gear ratios is fully automatic and is accomplished through the use of various electronic powertrain sensors that provide in- put signals to the Powertrain Control Module (PCM). ‘The PCM interprets these signals to send current to the various solenoids inside the transmission, By using electronies, the PCM controls shift points, shift feel and torque converter clutch apply and re- lease, to provide proper gear ranges for maximum fuel ‘economy and vehicle performance. Five multiple-dise clutches, one roller clutch, a sprag clutch, and a brake band provide the friction elements, required to obtain the various ratios with planetary ‘gear sets. A hydraulic system (the control valve body), pressur- ized by a vane type pump provides the working pressure needed to operate the friction elements and automatic controls, Several electronic solenoids and sensors in the power- ‘rain work in conjunetion with the vehicle’s PCM to control various shift points, shift feel and converter clutch apply and release, EXPLANATION OF GEAR RANGES Figure 8 The transmission can be operated in any one of the seven different positions shown on the shift quadrant (Figure 8). P— Park position enables the engine to be started while preventing the vehicle from rolling either forward or backward. For safety reasons, the vehicle’s parking brake should be used with the transmission in the “Park” position. Since the output shaft is mechanically locked to the case through the parking paw! and reaction inter- nal gear, Park position should not be selected until the vehicle has come to a complete stop. R— Reverse enables the vehicle to be operated in a rearward direction. N— Neutral position enables the engine to start and operate without driving the vehicle. If necessary, this position should be selected to restart the engine while the vehicle is moving. (©)— Overdrive range should be used for all normal driving conditions for maximum efficiency and fuel economy. Overdrive range allows the transmission to ‘operate in cach of the four forward gear ratios. When operating in the Overdrive range, shifting to a lower or higher gear ratio is accomplished by depressing the accelerator or by manually selecting a lower gear with the shift selector. ‘The transmission should not be operated in Overdrive range when pulling heavy loads. Typically these condi- tions put an extra load’ on the engine, therefore the transmission should be driven in a lower manual gear selection for maximum efficiency. D— Manual Third should be used when driving condi- tions dictate that it is desirable to use only three gear ratios, These conditions include towing a trailer or driv- ing on hilly terrain, Automatic shifting is the same as in Overdrive range for first, second and third gears ‘except the transmission will not shift into Fourth gear. 2~Manual Second gear range prevents the transmis- ‘sion from operating in any gear other than second. This allows the transmission to start moving the vehicle in second gear which may be helpful under slippery con- ditions such as snow or ice. Manual Second also pro- vides additional engine compression braking by not allowing the transmission to shift above second gear. Note: Some vehicle applications will downshift into {first gear when the transmission is in Manual Second under heavy throttle conditions at low speed. 11—Manual First can also be selected at any vehicle speed, however, the transmission will not shift into first gear until vehicle speed slows to below approxi- mately 48 to 56 km/h (30 to 35 mph). Above this speed the transmission will remain in second gear. Manual First is particularly beneficial for maintaining maxi- ‘mum engine braking when descending steep grades, FOLDOUT > 9‘SINANOdINOD TWOINVHOaIN SOVovert Bog s/n] |e] |a]x]a]a) |e +lelzfels|s|a|sfsls TAVHO JONaUIITY JONVE (9) econ go) asa 8 a3971 Yo109 aN3931 4010912 TORQUE CONVERTER TURBINE THRUST SPACER CONVERTER HOUSING ‘COVER ASSEMBLY “ ‘TORQUE CONVERTER: The torque converer (1) is the primary compo- nent for transmittal of power between the engine and the transmission, Its bolted tothe engine Aywhcot (also known as the Mlexpets) so that ‘will rotate at engine speed. The major functions ofthe torque converte are: + 10 provide a uid coupling for a smooth ‘conversion of torque from tne engine tothe me ‘Shania! eomponss ofthe tana, "ASSEMBLY © to multiply torque ffom the engine which enables the vehicle 10 achieve additional performance when required. + tommechanically operate the tansmission ofl pump (4) through the converter hub. *+ toprovidea mechanical link, or direct drive, from, the engine tothe transmission tarough the use of the torque converter clutch (TCC), or pressure plawe (©, The torque converter assembly consists of the following five main subassemblies: *+ aconverer housing eover assembly (A) which is bolted to the engine flywheel and 1s welded to the converter pump assembly (0). + aconverer pump assembly (} which isthe driv ing member. ‘+ a turbine assembly (F) whieh is the driven or ‘ouiput member. stator assembly (G) whichis the reaction mem- ter located between the converter pump ad tor bine asermblies + a pressure plate assembly (C) splined t the tur bine assembly fo provide a mechanical direct drive ‘when appropri CONVERTER PUMP ASSEMBLY AND ‘TURBINE ASSEMBLY ‘When the engine is running the converter pump assembly aets as a centrifugal pump by picking up Mui at is center and discharging i at its im Jetween the blades (See Figure 12). The force of this Muid then hits the turbine blades and causes the turbine to rotate, The turbine shat is splined to the converter turbine to provide the input to the transmission. As the engine and converter pump inerease in RPM, so does the turbine as- Sembly and turbine shat. However, withthe pres sie plate released turine spe! does not ex engine speed due to the small amount of slip that ‘occurs it a hud coupling PRESSURE PLATE. PRESSURE PLATE. SPRING THRUST BEARING ASSEMBLY w TURRINE ASSEMBLY STATOR ‘ASSEMBLY ‘CONVERTER PUMP NASSEMLY 6 o ) ToRUE oA F convERTER “Sse : a 6 RELEASED RELEASE LUD RETAINER ‘OAL ASsemBiy ‘em converte ry HUB inet i RELEASE aie) / RELEAS uraine SHAFT i - APPLY ALD E 6 ° appvy ti ree sortie Figure 11TORQUE CONVERTER PRESSURE PLATE, DAMPER AND CONVERTER HOUSING ASSEMBLIES ‘The pressure plate is splined to the turbine hub and applies (en- ‘zages) with the converter cover to provide a mechanical coupling ‘of the engine to the transmission. When the pressure plate assem: bly is applied, the small amount of slippage that occurs through 3 ‘uid coupling is eliminated, thereby providing a more efficient Itansfer af engine torque tn the transmission and drive wheels ‘The bottom half of the cutaway view of the torque converter in Figure 11 shows the pressure plate in the apply position while the 1p half shows the released position. Refer to Torque Con Release and Apply on pages 56 and 57 for an expla hydraulic control of the torque converter clutch To reduce torsional shock during the apply of the pressure plate to the converter cover, a spring loaded damper assembly (D) is used. The damper assembly is splined to the turbine assembly and the damper’s pivoting mechanism is attached to the pressure plate assembly. When the pressure plate applies, the pivoting Iechaniem allows the pressure plate to rotate independently of the damper assembly up to approximately 45 degrees. The cush- ioning effect of the damper assembly springs aid in reducing converter clutch apply fee! and irregular torque pulses from the engine or road surlace. ‘TURBINE ASSEMBLY O ‘CONVERTER PUMP. ASSEMBLY STATOR Figure 13 ‘STATOR HELD. FLUID FLOW REDIRECTED STATOR ROTATES Figure 12 STATOR ASSEMBLY ‘The stator assembly is located between the pump assembly and turbine assembly and is frounted on a roller cluteh, The roller clutch isa type of one-way clutch that prevents the Slator from rotating in a counterclockwise di= rection, The function of the stator is to redi- rect fluid returning from the turbine which ‘assists the engine in tuming the converter pump assembly, thereby multiplying torque. At low vehicle speeds, when greater torque is needed, fluid from the turbine hits the front side of the stator blades (converter multiply: {ng torque). The roller clutch prevents the si {or from rotating in the same direction as the fluid Now, thereby redirecting the fluid and increasing the Muid force on the pump assem- bly. Fluid from the converter pump then has more force fo tur the turbine assembly and Pretey. ‘multiply engine torque. |As vehicle speed increases, centrifugal force ‘changes the direction of fuid leaving the bine such that it its the back side of the stator blades (converter at coupling speed). When this occurs, the stator overruns the roller cutch ‘and rotates freely. Fluid is no longer redi- rected and torque is no longer multiplied 13This page intentionally left blankAPPLY COMPONENTS APPLY COMPONENTS The “Apply Components” section is designed to explain the function of the hydraulic and ‘mechanical holding devices used in the Hydra- ‘matic 4L60-E transmission, Some of these apply components, such as clutches and bands, are hydraulically “applied” and “released” in order to provide automatic gear range shifting, Other ‘components, such asa roller clutch or sprag clutch, often react to a hydraulically “applied” component by mechanically “holding” or “releasing” another, ‘member of the transmission, This interaction between the hydraulically and mechanically applied components is then explained in detail and supported with a graphic illustration, In addition, this section shows the routing of fluid pressure to the individual components and theit internal operation when the component applies ot releases. CUTAWAY BRIEF DESCRIPTION The sequence in which the components in this section have been discussed coincides with their physical arrangement inside the transmission. This order closely parallels the disassembly sequence used in the Hydra-matic 4L60-E Unit Repair Section located in Section 7 of the appropriate Service Manual. It also correlates with the ‘components shown on the Range Reference Charts that are used throughout the Power Flow section of this book. The correlation of information between the sections of this book helps the user to more clearly understand the hydraulic and mechanical operating principles for this transmission. MATING OR RELATED. COMPONENTS FUNCTIONAL DESACRIPTION \ DISASSEMBLED VIEW Figure 14 1516 APPLY COMPONENTS RETAINING RING (23) CUSHION RETAINER ‘SPRING RING a) 4 SERVO COVER (28). APPLY PIN, ATH APPLY PISTON (25) INNER ‘SERVO PISTON HOUSING (20) 2ND APPLY PISTON iy RETURN SPRING 2) RETAINER ‘SERVO ASSEMBLY and 2-4 BAND CASE @ SPRING 24 a5) ASSEMBLY (602) BAND The servo assembly and 2-4 band (602) are located in the front of the transmission case ‘and applied in Second and Fourth gears. In Third geat, like server assembly relenes the band and acts as an ‘accumulator for the 3-4 clutch apply. The band is held Stationary tothe transmission cease by the band anchor pin (49) and wraps around the reverse input housing (605). When compressed by the servo assembly, the 2-4 band holds the reverse input housing stationary to the transmission ease. BAND ANCHOR PIN (aT) 2-4 Band Applied - Second Gear To apply the 2-4 band in Second gear, 2nd clutch Muid is routed to the apply Side of the 2nd apply piston (17). 2nd clutch fluid pressure moves the piston against servo cushion (16) and servo re~ turn (12) spring forces. These spring forces help cushion the 2-4 band apply in Second gear. The 2nd apply piston moves the apply pin (13) to compress the band around the reverse input hous ing. 2-4 Band Release and 3-4 Clutch ‘Accumulation In Third gear, 3rd accumulator fluid is routed to the release side of the 2nd a\ ” CHECKBALL apply piston, The surface area on the release side of the 2nd apply piston (17) and servo cushion spring fetainer (15) is greater than the surface area that 2nd clutch fluid pressure covers on the ap- ply side of the piston, ‘Therefore, the Torce from 3rd accurulator fluid pres- sure, in addition to servo return spring (12) force, overcomes the force of 2nd clutch fluid pressure. The 2nd apply piston then moves the apply pin (13) way from the 2-4 band to release the ‘band from the reverse input housing, 3rd accumulator fluid is fed by 3-4 clutch fluid which is used to apply the " CHECKBALL 3-4 clutch, The movement of the 2nd apply piston against 2nd clutch fluid pressure acts as an accumulator to ab: sorb initial 3-4 clutch apply fluid, This, action helps cushion the 3-4 clutch ap- ply, as well as release the 2-4 band, 2-4 Band Applied - Fourth Gear In Fourth gear, 4th fluid is routed through the center of the apply pin and acis on the apply side of the 4th apply piston (25). 4th fluid pressure moves the 4th apply piston (25) and apply pin (3) to apply the band. The 4th apply piston moves against the 4th apply spring, (22) to help cushion the band apply in Fourth gear, a CHECKBALL EX" 2NDY SRO" ATH cLUICH Accum ‘SECOND GEAR - 2-4 SERVO APPLIED EX 2NDY RD SATA CLUTCH Accum ‘THIRD GEAR - 2-4 SERVO RELEASED cLUTGH accom FOURTH GEAR - 2-4 SERVO APPLIED Figure 15,APPLY COMPONENTS REVERSE INPUT CLUTCH ‘The reverse input clutch is located in the reverse input housing (605) and is used to provide an input ‘0 drive the vehicle in Reverse (R). Tae steel clutch plates (612A) are splined to the reverse input REVERSE housing while the fiber clutch plates INPUT HOUSING (605) Reverse Input Clutch Applied “To apply the reverse input clutch, reverse input fluid is fed from the oil pump, through the stator Shaft (214) and to the reverse input housing. Feed holes inthe inner hub of the reverse input housing. allow reverse input fd to enter the housing be- hind the reverse input clutch piston (607). Any air in the reverse input fluid circuit will exhaust ‘through the fluid bleed hole to prevent excess cush- jon during the clutch apply. As fluid pressure increases, the piston compresses the steel, fiber and belleville (611) clutch plates together until they are held against the reverse input clutch back- ing plate (613). The backing plate is splined to the housing and held in place by the retaining ring (614). With the clutch plates applied, the belleville plate is compressed to cover the fluid bleed hole and prevent fluid from exhausting. The belleville plate also funetions to assist spring force in cushioning the clutch apply. When fully applied, the steel and fiber plates are locked together to hold the reverse input housing and input housing together. Reverse Input Clutch Release To release the reverse input clutch, reverse input fluid exhausts from the reverse input housing and back through the stator shall, Without Muid pres- ‘sure, force from the piston spring assembly and belleville plate moves the reverse input clutch pis- ton away from the clutch pack. This disengages the clutch plates from the backing plate and dis ‘connects the reverse input housing from the input housing assembly. Centrifugal force, resulting from the reverse input housing rotating, forees residual fuid to the out- side ofthe piston cavity. During the clutch release the belleville plate moves away from the Muid bleed hole. This allows residual fluid atthe out- side of the piston housing to exhaust through the bleed hole. If this fluid did not completely ex- Ihaust from behind the piston there could be a par- tial apply, oF drag ofthe reverse input clutch plates REVERSE INPUT HOUSING. (605) ourer SEAL (608) PISTON ASSEMBLY BELLEVILLE PLATE (er) (612B) are splined to the input housing and turbine shaft assembly (621). When ‘applied, the reverse input elutch transfers ‘engine torque from the input housing to the reverse input housing. ‘SPRING ASSEMBLY (603) RETAINING. RING, (610) SELECTIVE ‘BACKING PLATE (613) RETAINING. RING. ea) STEEL PLATE (612A) 613 os Figure 16 7APPLY COMPONENTS ‘OVERRUN CLUTCH ‘The overrun clutch assembly is located in the input housing ‘and turbine shaft assembly (621) and is only applied in the Manual Gear ranges. The steel clutch plates (645A) are splined to the input housing while the fiber clutch plates (645B) are splined to the overrun clutch hub (639), When applied, the overrun clutch plates force the overrun clutch hhub to rotate at the same speed as the input housing. This prevents the forward sprag clutch from being overrun during ‘oast conditions, thereby providing engine compression brak= ing o slow the vehicle ‘OVERRUN CLUTCH CHECKBALL Overrun Clutch Applied RELEASED Toapply the overrun clutch, overrun clutch fluid is routed through the turbine shaft and into the input housing be- hind the overrun clutch piston (632). Overrun clutch fluid pressure seats the overrun clutch checkball (633), which is located in the overrun cluch piston, and moves the piston to compress the overrun clutch spring assem- bly (634). Any’airin the overrun clutch fluid circuit will exhaust pas the checkball before it fully seats to prevent OVERRUN STEEL FIBER excess cushion during the clutch apply. As fluid pres- nnn oe ea nrc torre sure increases, the piston compresses the steel and fiber PISTON PLATE. PLATE clutch plates together until they are held against the for- ward clutch apply plate (646). When fully applied, input the steel and fiber plates are locked together and HOUSING hold the overrun clutch hub to the input housing. ‘SHAFT ‘Overrun Clutch Released OVERRUN Porctene the oven eth, any Grosur such iadexnuse ATT Sean te input atop sod Tr ett ne arte an. Widow 1a presse fore, om the piston sping asebly moves reocemea tach isarty ne tuck pucks dgenpges the lh pate othe Mestad ash i pas an dpomons he ‘Nenu etch Ab erste ipa hos. ‘OUTER INNER During the exhaust of overrun clutch fluid, the overrun ‘SEAL SEAL ASSEMBLY clutch checkball unseats (see illustration). Centrifugal je GH) (e3) force, resulting from the input housing rotating, forces: residual overrun clutch fluid to the outside of the piston hhousing and past the unseated checkball. If this Muid did not completely exhaust from behind the piston there ‘could be a partial apply, or drag of the overrun clutch plates. 2632435 GASA, 02:00) Figure 17APPLY COMPONENTS FORWARD CLUTCH The forward clutch assembly is located in the input housing and turbine shaft assembly (621) and is applied in all forward drive ranges. Thee steel clutch plates (649A) are splined to the input housing while the fiber elutch plates (649B) are splined iwpur 10 the forward clutch outer race (644), When applied, the a ~HOUSNG —finsvaid clatls plates tans engine (orgue om dhe inpat SHAFT (621) housing to the forward clutch outer race and forward sprag clutch assembly. Forward Clutch Appliod ‘To apply the forward clutch, forward clutch feed fluid FORWARD CLUTCH HOUSING CHECKBALL is routed through the turbine shaft and into the input “APPLIED RELEASED ‘housing behind the forward clutch piston (630). For= ‘ward clutch feed fluid pressure seats the forward clutch housing checkball, whieh is located in the forward htc housing (62), and mover te ison (0 com ‘ess the piston spring assem ay aie in the Fonwart cute feel fail cnc will xis past the Sheekball before it fully seats to prevent excess cu n during the clutch apply. As fluid pressure i regen, he pnt grove hs apply lat (46) and SPRING APPLY WAVED SELECTIVE RETAINING until they are held against the selective forward clutch ee EAT ATE eas tacking plate (650) The backing plate, which i se Ce Oe ean lective for assembly purposes, is splined to the input ‘housing and held in place by the retaining ting (651), ‘Also included in the forward clutch assembly is. ‘a stee! waved piate (648) that, in addition to the Spring asscinbly, helps cushion the clutch apply When fully applied, the stee! and fiber plates an looked ogee and hl the int housing and forward clutch outer race together. rorwaro cuurc TURBINE FORA CUD Forward Clutch Released ‘Torelese the forward cits, forward clutch fed id exists fo the input housing and back through the turbine sat. ‘Without Hid presse, fore fom the piston Sing scenbly and wave plat nova the a a clutch’ re ae foe ee ‘hin dsengager the chtch plates Trom the beck plate and disconnets the input housing fom the foe ‘var latch outer ace During the exhaust of forward clutch feed fluid, the forward clutch housing checkball unseats (see illus- tration). Centrifugal force, resulting from the input SEAL-SEAL CLUTCH SEAL CLUTCH PLATE PLATE housing rotating, forees residual forward clutch feed (22) (628) HOUSING (628) PISTON. (649A) (6498) fluid to the ouside of the piston housing and past the (628) (630) ‘unseated cheekball. If this fluid did not completely ‘exhaust from behind the piston there could be a partial apply, or drag ofthe forward clutch plates. 27 628 630 632634635645 BAB GADA, 6498650. 651 19APPLY COMPONENTS 3-4 CLUTCH ‘The 3-4 clutch assembly is located in the input housing and turbine shaft assembly (621) and is applied in Third and Fourth gears. The steel clutch plates (654B/C) are splined to the input housing while the fiber clutch plates (654A) are splined AIR BLEED ‘ORIFICE CUP PLUG. (658)——9 to the input internal gear (664). When applied, the 3-4 clutch INPUT plates casfer engine lorque fn the input housing Wo Ure TURBINE HOUSING Input internal gear SHAFT ean) 24 CLUTeH cHECKBALL 2-4 Clutch Applied pp.se0 RELEASED To apply the 4 clutch, 3-4 clutch Midis routed though the turbine shaft and into the input hosing behind the 34 cluch piston (623). 5-4 clutch fui pressure seats the 34 latch checkbal (620), which located inthe tpt housing, ad moves the piston enna the 3-4 luc apply ving (638). The apy Ting” compresses the ‘- clteh spring assembly (626) which helps cushion the 34 clutch ppl. Any sir inthe 3-4 eltch ld cirout will exhaust past 7 Prive STEP 7 RETAN the 34 each ehekbal before i ily sats o re= SSTON ASSEMBLY APPLY SPRING "RING ‘ent excess cushion dicing the clutch apy (e2)“Steaa. PLATE “(6o0) A fluid pressure increases, the apply ring moves aginst the retainer ring plate (682) and stepped ap Bly plats (653). This fore compresses the sel and Fer clutch plates (658) together unl ey are held guna the selective 3-4 cltch backing plate (655). ‘he backing plate, whichis selective far assembly purposes, is splined to the input housing and held In place bythe retaining ring (656) 3.4 CLUTCH ane APPLY FLUID 2-4 cimten Roteasoa Torelease the 3-4 luch, 3-4 clutch Nuid xhausts fom te input housing and back through he trbine shat Without Mid presnie, free om the piston spring assem- S Uy an oest springs (60) suo di ded htc Sa apply ting and piston away from the clueh pack. I ‘This disengages the clutch plates Som the Bacing plate and disconnects the input housing fron the forward elutch outer ace During the exhaust of 3-4 uth Nui, the 3-4 latch Checkblluneats (or nusuatin). Centifugalforee, ARSLEED OUTER INNER 3-4CLUTCH RETAINER STEEL FIBER itn Ranh nut henioe ane Reeeere, JORGE “SEAL” ‘SEAL APPLYRING “RING.” PLATE PLATE Sunes tak glee he ase eee tan CURAUG a) Tea) “TINS UNE SIA) th Housing and past the unseated checkball I this Aid didnot completely exhaust fom behind the piston thete could bea partial apply, ar dag oF the BSF cuth plates (652) 623 625628 652 653 6540 6540, 6545655656 vn) We eS 1) \| id aaa) Figure 20APPLY COMPONENTS FORWARD CLUTCH 'SPRAG ASSEMBLY (638-644) Forward Sprag Clutch Holi ‘When the forward clutch is applied, engine torque is transferred to the forward clutch race (644) which functions as the outer race for the sprag assembly. The rotation of the outer race pivots the ‘pags toward their long diagonals. The length of the long diago- nal (distance A) is greater than the distance between the outer race ‘and inner race (641). This eauses the sprags to “lock” between the inner and outer races and transfer engine lorque from the forwerd clutch race to the inner race and input sun gear (658) SPRAG CLUTCH HOLDING ‘OUTER RACE DRIVING THE INNER RACE SPRAG CLUTCH RELEASED. INNER RACE ROTATES FASTER THAN OUTER RACE ourer RACE (64) RACE: a) Forward Sprag Clutch Released ‘The sprag clutch releases when the sprags pivot toward theit short diagonals. “The length of the short diagonals (B) 1s less ‘than the distance between the inner and outer sprag races. This ‘occurs when power flow drives the input sun gear and sprag race and retainer assembly faster than the forward clutch drives the forward clutch race (644). During acceleration the sprag clutch is overrun only in Fourth gear. Coast Conditions ‘The sprag clutch is also overrun during coast conditions, or deceleration, inthe following gear ranges: = Overdrive Range - Firs, Second and Third Gears Manual Third - First and Second Gears = Manual Second - First Gear FORWARD SPRAG CLUTCH ASSEMBLY ‘The forward sprag clutch assembly (642) is located between the forward clutch race (644) and the sprag race & retainer assem- bly (641). The sprag race and retainer is connected to both the ‘overrun clutch hub (639) and input sun gear while the forward clutch race is splined to the forward clutch plates. The spraz ‘clutch is a type of one-way clutch that transfers engine torque from the forward clutch to the input sun gear during acceleration st, Second and Thisd gears in Overdrive Range. When the throttle is released in these gear ranges the sprag clutch is over- run fo allow the vehicle to coast freely. SPRAG. RETAINER 643) During coast conditions, power fiom vehicle speed drives the input sun_gear faster than engine torque drives the forward clutch race (644). In ths situation, the sprag race and retainer assembly (641), which is splined to the sun gear, overruns the sprag clutch and allows the vehicle to coast freely. Overrun Clutch Applied ‘When the overrun chutch is applied (see range reference chart) it hholds the overrun clutch hub and sun gear together, These ‘components are then forced to roiate at the same speed as the input housing. This prevents the input sun gear from being. driven faster than the Forward clutch face (644), ‘During coast conditions when the throttle is released, power from vehicle speed i then trnsferred back to the torque converter and engine ‘compression slows the vehicle, Figure 20, 222 APPLY COMPONENTS LO ROLLER CLUTCH ‘The lo roller clutch (678) is a type of one-way clutch used 10 ‘prevent the reaction carrier assembly (681), reaction carier shaft (666) aad input internal gear (664) from rotating ia a counter- ‘clockwise direction. The roller clutch is located between the fo & reverse clutch support (679) and the lo roller clutch race (675). The lo roller clutch support functions as the outer cam forthe roller clutch and is splined to the transmission case, The roller clutch race (675) is splined to the reaction cartier assem- bly (681) and functions as the roller clutch inner race. LO ROLLER ‘cLUTCH ASSEMBLY (675.679) Roller Clutch Holding ‘The roller clutch is holding during acceleration in First gear. ‘When accelerating in First gear, he reaction carrier assembly and inner race (675) attempt to rotate counterclockwise. This faction causes the rollers to oll up the ramps on the outer eam and wedge between the inner race and outer cam. With the rollers wedged and the lo and reverse clutch support eld sta tionary tothe transmission case, the reaction carrer assembly is, also held stationary. ROLLER CLUTCH HOLDING. ROLLERS HELD Low REVERSE ROLLER cuurcH cLuTcH SUPPORT RACE (679) 5) Roller Clutch Released ‘The roller clutch is overrun by the reaction carrier assembly and, inner race when the throttle is released during First gear opera: tion with the selector lever in Overdrive, Manual Third and ‘Manual Second. Whea the throttle is released, power flow from, vehicle speed drives the reaction catrer assembly and inner race in a clockwise direction. The inner race moves the rollers down, the ramp, overruns the rollers and rotates freely in a clockwise Sreceoeead Lo and Reverse Clutch Applied ROLLER CLUTCH RELEASED In Manual Fist» First Gat, the lo and reverse clutch is applied {0 hold the reaction carrier assembly stationary to the transmis~ sion ease. The lo and reverse clutch prevents the reaction car- trict and inner race from rotating clockwise and overrunning the roller clutch when the throtle is released. Power flow is then ROLLERS transferred back through the transmission gear sets and to the FREE” torque converter, allowing engine compression to slow the ve~ ROLLER _hicle. ‘The lo and reverse clutch is also applied in Reverse to LO& REVERSE & REVER CLUTCH provide he necessary power flow to obain Reverse SUPPORT RACE er am 679 67 2 os 67 oe Figure 21APPLY COMPONENTS LO & REVERSE CLUTCH ASSEMBLY Lo and Reverse Clutch Applied ‘To apply the fo and fevers clutch, wo dif ferent fluids are routed t0 the lo and reverse clutch piston (695). In Manual First, loie= verse fluid is routed tothe inner area of the clutch piston In Pak and Reverse, PR fuid is routed to the outer area of the fo and re- verse clutch piston, in addition to loteverse Tuid acting on the inner area of the piston, 10 provide greater holding capacity of the Clutch. Fluid pressure moves the piston to compress the lo and reverse clutch pision spring assembly (634). PR Muid seats the PR checkball and is orificed tothe piston to help ‘control the clutch apply. Also included inthe forward clutch assembly isa stel waved plate (GA2A) that in ation t the spring assem bly, helps cushion the clutch apply. As fuid pressure increases, the piston compresses the Steel and fiber clutch plats together until hey are held against the lo and reverse support assembly (679), which is also splined tothe transmission case. The spacer plate (682B) is selective for assembly purposes. Lo and Reverse Clutch Released To release the lo and reverse clutch, apply fluid pressure exhausts from the behind the land reverse clutch piston. When exhaust- ing, PR fluid unseats the PR checkball (42) for a quick exhaust. Without fluid pressure, force from the piston spring assembly and waved plate moves the Io and reverse clutch piston away from the eluteh pack. This dis- ‘engages the clutch plates from the lo and re- ‘verse clutch suppor, thereby allowing the re action carrier assembly to rotate freely 676 619 682c LO AND REVERSE CLUTCH ‘The lo and reverse clutch assembly is located inthe rear of| the transmission case and is applied in Park, Reverse and Manual First - First Gear. The steel clutch plates (682A,B,D) are splined to the transmission case while the fiber cluich plates (682C) are splined to the reaction plan- ‘tary carrier (681). Whon applied, the lo and reverse clutch pilates hold the reaction planetary carrier stationary to the LOM REVERSE RETAINER FIBER STEEL QUTER CENTER SUPPORT” "RING PLATE PLATE “Seal “SEAL ASSEMBLY (018) (6820) (6820) — 699) (088) ier ===, or ¥ @) i U A) | LO & REVERSE i) {) CLUTCH cas “a (695) NER ‘SEAL (695) LOMEVERSE SELECTIVE WAVED FLUID FLUID ‘SPACER PLATE PLATE (682A) (828) ‘APPLIED RELEASED DOUBLE ORIFICE RETAINER & BALL ASSEMBLY (2) 6ez0 Gaze GAA aus 695 Figure 22 23PLANETARY GEAR SETS REDUCTION - FIRST GEAR REACTION ea ‘CARRIER ‘SHAFT CARRIER ASSEMBLY = HELD | J TRANSMISSION CASE (®) ourpur REACTION rercrion NUE CARRIER, “guy ASSEMBLY pfIVEN (ean) HELD 673) REDUCTION - SECOND GEAR REACTION CARRIER inpur CARRIER ‘ASSEMBLY eabrow rencrion TERNAL retenge Gene aes, SEY opin es Figure 23,PLANETARY GEAR SETS DIRECT DRIVE - THIRD GEAR input reaction SHAT chet, CEM “canaier (27 62) Biiety (66 SHAT ven ees) DRIVING ay (655) DRIVEN \> REACTION INTERNAL, GEAR mur GEAR ‘SUN. DRIVEN GEAR (658) DRIVING. OVERDRIVE - FOURTH GEAR ‘TRANSMISSION ‘CASE (ean) DRIVING REACTION CARRIER ASSEMBLY (a1) REDUCTION - REVERSE ‘TRANSMISSION ourrur Ae ar 3 on sz REACTION REACTION EASSe NfeaNA REACTION, ASSEMBLY GEAR Sear (eax) (ees) cr fed kiven DRIVING Figure 24 iThis page intentionally left blankHYDRAULIC CONTROL COMPONENTS ‘The previous section ofthis book describes the operation of the mechanical components used in the Hydra-matic 4L60-E trans mission. In this section, a detailed description ofthe individual components used in the hydraulic system will be presented, ‘These hydraulie control components apply and release the clutches, band and accumulators that provide for the automatic shifting ofthe transmission ae See Be em) 20)” yor sraron ae ae fo J suoe sling @ RNG ‘SEAL O-RING SEAL SEAL ING ‘SEAL Gen) SUPPORT (201) (202) had (208) ll PUMP ASSEMBLY The oil pump assembly (4) contains a variable displacement vvane type pump located in the oil pamp body (200). The oil pump rotor (212) is keyed to the torque converter pump hub. ‘Therefore, when the engine is running the converter pump hub drives the rotor at engine speed. AS the oil pump rotor and the cil pump vanes (213) rotate, the area between the vanes creases and fluid volume is positively displaced, thereby creat ‘ng a vacuum at the pump intake port. The vacuum force allows, latmospherie pressure acting on the Muid in the bottom pan to prime the pump and pressurize the hydraulic system. Fluid from the transmission bottom pas is drawn through the oil filter assembly (72) and into the oft pump intake Auld citeuit, ‘This ud is forced into the oil pump through the intake port and rotates around the oil pump slide (203) to the pump outlet port. As the fluid rotates around the slide, the volume between the /pump vanes decreases before reaching the outlet port. Decreas- ing the volume pressurizes the fluid and forces the fluid into the line pressure fluid eircuit. This fluid is directed to the pressure regulator valve and becomes the main supply of fluid to the various components and hydraulic circuits in the transmission, Figure 25 2128 HYDRAULIC CONTROL COMPONENTS COMPONENTS LOCATED IN THE OIL PUMP ASSEMBLY ‘Torque Converter Clutch Solenoid ‘The Powertrain Control Module (PCM) controls the TCC sole- noid to apply and release the converter clutch, The TCC sole- noid is a normally open, ON/OFF solenoid that, when energized (ON), initiates the converter clutch apply. Refer to the Elee- tronic Component Section for a complete description of the TCC solenoid. ‘Torque Converter Clutch Apply Valve (224) Controlled by the TCC solenoid state and converter clutch sig- nal fluid pressure, it directs converter feed fluid pressure to either the release or apply side of the converter clutch. The TCC apply valve also directs fluid into the cooler fluid circuit, ‘The valve is held in the release positon (as shown) by spring force when the TCC solenoid is OFF. With the TCC solenoid (ON, converter eluich signal Muid pressure increases and moves: the valve into the apply postion agsinst spring force. Pressure Regulator Valve (216) Regulates line pressure in relation to vehicle operating condli- tions (see page 29 on Pressure Regulation). The pressure regu- lator valve is biased by torque signal fluid pressure, pressure regulator spring (217) force, line pressure routed to the end of the valve, and reverse input fluid pressure acting on the boost ve in Reverse. Line pressure is routed through the valve and into both the converter feed and decrease fluid circuits Boost Valve (219) ‘Torque signal fluid pressure moves the boost valve against the isolator spring (218). The isolator spring then exer the Force from torque signal Muid pressure to the pressure regulator valve. ‘Therefore, line pressure increases as throtle position and engine torque increase, Also, reverse input fluid pressure acting on the ‘boost valve inereases the operating range of line pressure when, the transmission isin Reverse, om 7 = Yq Be a 7 4 ae i 229 % 80 (220) g bee 5 @, m oa 228 a 3 m 2 as oon a os, om, mm | ) ues veut _ 2 222 8 es a “s 2 g 4 1 z Q Pressure Relief Bal (228) ‘The pressure relief ball and spring (229) prevent Tine pressure from exceeding approximately 2240 to 2520 kPa (320 10 360, psi), Above this pressure, line Muid pressure moves the ball, Against spring force and exhausts until line pressure decreases sufficiently Retainer and Checkball Assemblies (237) ‘These two assemblies are located inthe reverse input andl over- ‘un clutch fluid circuits. Their function is to allow ais to escape from the lui circuit when fluid pressure increases during clutch apply. Also, when the clutch releases the ball unseats and allows air into the circuit o displace the exhausting fluid, Orifice Cup Plugs (239-240) ‘Various office cup plugs are located in the oll pump cover 15) to provide fluid flow contro in the transmission’s hydrau- lie system. Figure 26HYDRAULIC CONTROL COMPONENTS PRESSURE REGULATION PRESSURE REGULATION The main components that control line pressure are the pressure ‘control solenoid and pressure regulator valve. The fluid pres Sure required to apply the clutches and band varies in relation te throttle position and engine torque. At the pressure regulator ‘valve line pressure is regulated in response to the following: += torque signal fluid pressure routed from the pressure con ‘rol solenoid (PCS) (this fluid pressure is proportional to engine torque - see page 40), Torque signal fluid pressure moves the boost valve (219) against the pressure regulator isolator spring (218) which acts against the pressure regula- tor valve, pressure regulator spring force Tine pressure acting on the end of the pressure regulator valve. reverse input fluid pressure acting on the boost valve in Reverse “The pressure regulator valve routes line pressure into both the ‘converte feed and decrease fluid circuits, Converter feed fluid is routed to both the torque converter and cooler Muid circuits. Decrease fluid pressure moves the oil pump slide against the force of the pump slide springs (outer - 206, inner ~ 207). Decrease fluid pressure and the position of the pump slide con- ‘tantly vary in relation to torque signal fluid pressure and engine torque as controlled by the pressure regulator valve. LINE (To Manual Ve) (MINIMUM PUMP OUTPUT Minimum Pressure Regulation When engine torque is @ minimum, the PCS regulates torque signal fluid pressure to a minimum, During these conditions, Tine pressure acting on the end of the pressure regulator valve moves the valve against spring force and torque signal fluid pressure to a point where line pressure entcrs both the converter feed and decrease fluid circuits. Decrease fluid pressure moves. the pump slide (203) against spring force and toward the center of the pump body, causing the slide to partially cover the pump intake port This increases the concenitiety between the pump slide and rotor which decreases the vacuum affect on the Muid,, thereby decreasing line pressure, ‘Maximum Pressure Regulation When engine torque is a maximum, the PCS regulates torque signal fluid pressure to a maximum. Maximum torgue signal fluid pressure moves the boost valve against the isolator spring, to increase the force on the pressure regulator valve. This, moves the pressure regulator valve to block line pressure from entering the decrease fluid circuit. With lower decrease fluid pressure, pump slide spring force moves the slide against the side of the pump body. This decreases the concentrcity be- twwoen the slide and rotor which increases the vacuum affect on the fluid, In this positon line pressure is a maximum. The ‘output ofthe oil pump continuously varies between these mini- ‘mum and maximum points depending on vehicle operating con- ditions LINE (To Maru Ve) TORQUE SIG MaxiMUM PUMP OUTPUT Figure 27HYDRAULIC CONTROL COMPONENTS ‘COMPONENTS LOCATED IN THE VALVE BODY 1-4 Shift Valve (385) Biased by signal "A" Aid pressure from shift solenoid “A’ spring force and D3 fluid pressure, the 3-4 shift valve controls the routing of 3-4 signal fluid, To obiain Fourth gear, signal “A” fluid pressure moves the valve against spring force and dineets 3-4 signal uid into the dls sigial uid eiscuit, How ever, in Manual Third, D3 fluid assists spring force and holds the valve against signal “A Muid pressure to prevent Fourth ‘gear under any conditions. In the downshifted position, the 4th jgnal fluid citeuit is open to an exhaust past the valve. 3-2 Downshift Valve (389) ‘The 3-2 dowashifl valve helps control the 2-4 band apply rate during a 3-2 downshift. During the downshif, 34 clutch fluid pressure holds the valve against spring force before exhausting, ‘This allows 2nd fluid to quickly fll the 2nd clutch uid cireutt, for a faster 2-4 band apply. Reverse Abuse Valve (387) ‘The reverse abuse valve provides a faster apply of the reverse input clutch when throttle position is greater than idle. During these conditions, reverse fluid pressure inereases and moves the valve against spring force. Reverse fluid can then quickly fill the reverse input fluid circuit. This bypasses the control of the reverse input orifice (#17) fora faster clutch apply. 3-2 Control Solenoid (384) ‘The 3-2 control solenoid is normally closed and controls the timing between the 3-4 clutch release and the 2-4 band apply during a 3-2 downshift. This is done through the use of pulse jdth modulation (duty cycle operation). The solenoid’ duty eyele is controlled by the PCM in relation to vehicle operating conditions and regulates actuator feed limit (AFL) fluid into the 3-2 signal fluid circuit. 3-2 Control Valve (391) ‘The 3-2 contol valve regulates the exhaust of 3rd accumulator uid into the 3-4 clutch fluid cireuit during a 3-2 downshift ‘This regulation is controlled by 3-2 signal fluid pressure from the 3-2 control solenoid, 3-2 signal Muid pressure moves the valve against spring force to open exhausting 3rd accumulator ‘uid to the 3-4 clutch fluid circuit. The amount the valve is, ‘opened to exhaust 3rd accumulator fluid controls the 3-2 down- Shift imi ‘Manual Valve (340) ‘The manual valve is supplied line pressure from the pressure regulator valve and is mechanically linked to the gear selector lever. When a gear range is selected, the manual valve directs line pressure into various circuits by opening and closing fluid passages. ‘The fluid eircuits fed by the manual valve include Reverse, PR, D4, D3, D2 and lo. Pressure Control Solenoid (377) Controlled by the PCM through a duty eycle operation, the pressure conirol solenoid (PCS) regulates AFL fluid pressure into the torque signal fluid circuit, Torque signal fluid pressure is regulated in response to engine torque and other vehicle oper- ating conditions. Torque signal fluid pressure is routed to the boost valve to increase line pressure and to the accumulator valve to help control shift fel. ‘Actuator Feed Limit Valve (374) ‘The AFL valve directs line pressure into the AFL fluid circuit, Spring force acting on the valve limits AFL fluid pressure to 8 ‘maximum of approximately 795 kPa (115 psi). When line pressure is above this vale, orficed AFL. fluid pressure moves the valve against spring force to block line pressure, thereby providing the limiting action. AFL fluid is routed to the shift solenoids, pressure control solenoid, 3-2 control solenoid and, the 2-3 shift valve tain, Converter Cluteh Signal Valve (380) ‘The CC signal valve controls the routing of line pressure into the CC signal fluid cireut. 2nd clutch fluid pressure opens the valve in Second, Thied and Fourth gears to direct line pressure io the CC signal Mud circuit 3-4 Relay Valve (384) and 4-3 Sequence Valve (383) ‘These valves are used mainly to control the 4-3 downshift tim- ing. The valves direct various fluids into different fluid circuits depending on the gear range. Spring force acting on the 4-3 sequence valve tends to keep the valves in the downshifted position, In Fourth gear, 4th signal fluid pressure moves both valves against spring force and into the upshifted position (see Overdrive Range: 4-3 Downshil on page 58). OVERRUN CL 4 ACOUM SERVO FD “OVERRUN 8 ‘oveRRuN ct 0: aH SERVO FD z SIGNAL A. ° FERED 34a. reverse] 5 Bos | © ewe SSH] VALVE BODY Figure 28HYDRAULIC CONTROL COMPONENTS ‘COMPONENTS LOCATED IN THE VALVE BODY ‘Aecurnulator Valve (371) ‘The accumulator valve is biased by torque signal fluid pressure, spring force and orificed accumulator Hluid pressure atthe end ‘of the valve. The valve regulates D4 fluid into accumulator fluid pressure in relation t© engine torque, as determine by longue signal Nui pressuse, Aveumuliton Mud pressure i used to control shift fee! during the 1-2 and 3-4 shifts. During the 1-2 and 3-4 upshifs, the valve regulates the exhaust of accumulator fluid to help control shift Fel SERVO FD g 8 cH onessune | coneon | bi} | Souenow | & ——————70 ACCUMULATOR 03 ‘ORIICED EX 2n0 Oairiceo ex ek ACTUATOR FD LIMIT Lonsr LOmREY PR Fi ct ro ‘Shift Solenoid "B” (367) Located at the end ofthe 2-3 shuttle valve, shift solenoid “B” is anormally open, ON/OFF type solenoid controlled by the PCM. ‘The solenoid is used to control solenoid signal fluid pressure at, the end of the 2-3 shuttle valve and the positioning of 2-3 shift, valve train. When de-energized, the solenoid is open and sole- noid signal fluid exhausts through the solenoid. When ener~ tized, the solenoid is closed and blocks solenoid signal fluid from exhausting, thereby ereuting solenoid signal fluid pressure atthe end of the 2-3 shutle valve. 2.3 Shift Valve (368) and 2-3 Shuttle Valve (369) ‘The 2-3 shift valve tain responds to AFL fluid pressure acting ‘on the 2-3 shift valve and solenoid signal fluid pressure from shift solenoid “B” at the 2-3 shuttle valve. Also, in Manual ‘Second and Manual First gear ranges, D2 fluid pressure is routed between the twa valves 17 Aid pressure keeps the 2-4 shift valve in the downshifted position to prevent the transmiss from upshifting above Second gear regardless of shift solenoid, sates, The valve train controls the routing and exhausting of various fluids to obtain the appropriate gear range as determined, by the PCM or gear selector lever. ‘Shift Solenoid “A” (387) Located atthe end of the 1-2 shift valve, shift solenoid “A” is a normally open, ON/OFF type solenoid controlled by the PCM. ‘The solenoid is used to control signal “A” Muid pressure and the positioning of both the 1-2 shift valve and the 3-4 shift valve, ‘When de-cnergized (OFF), the solenoid is open and signal “A ‘Tuid exhausts through the Solenoid. When energized (ON), the solenoid is closed and blocks signal “A” fluid from exhausting, thereby creating signal “A” fluid pressure at the 1-2 and 3-4 shift valves, 1-2 Shift Valve (366) Tho 1-2 chit valve i biaced by cignal “A” uid proseure, spring force and D432 Muid pressure. The valve position depends on the shift solenoid states. Shift solenoid “A” controls signal “A” fluid pressure and shift solenoid “B” controls the 2-3 shuttle valve position and D432 fluid pressure. The 1-2 shift valve directs D4 fluid into the 2nd fluid circuit to upshiftthe transmis sion to Second gear. The valve also routes lo fuid into the lo! Ist fluid eireuit im Manual Fist - First Gear. The exhaust past the valve isan annulus exhaust ia which exhausting fluid, either 2nd fluid or lo Ist uid, flows around the valve land and through the valve body. Forward Abuse Valve (387) ‘The forward abuse valve provides a faster apply of the forward, clutch when throtle position is greater than idle. During these conditions, Dd fluid pressure increases and moves the valve ‘against spring force. D4 fluid can then quickly fll the forward, clutch feed fluid circuit. This bypasses the control of the for- ‘Ward clutch accumulator orifice (222) fora faster elutch apply Lo Overrun Valve (361) In Reverse, PR fluid moves the valve against spring force and Fills the loteverse fluid circuit. In Manual First, the lo overrun vale regulates lo!lst fluid pressure into the Toireverse fluid circuit. This regulation is biased by spring force and oritieed lo’ reverse fluid pressure acting on the valve. Forward Clutch Accumulator Forward clutch accumulator spring force absorbs the initial in- crease in Forward clutch feed fluid pressure to cushion the for ‘ward clutch apply. Refer to page 32 for a complete description of accumulator function, Note: Refer to the “Power Flow" and ‘Complete Hydraulic CCreuit sections fora detailed explanation of each components ration ina spectfie gear range. Also, referto the ‘Electron Component section for a detailed description of each elec tranie component 31‘voz annb4 ezamis ‘aye Owe” asnyexa L wranassy ons 2 saouwinwngoy ‘suoninwngoy ups ‘rung es SLNINOdINOD 1ONLNOD SIINWAGAH(033470 Mat 20 cRa1sRi NOHONAY GN NOLLWI01 TIVENOIHO ineRIAO SLNANOdINOD TONLNOD SIINVYGAH NOUNS aNY NOUVI0 TvExO3HDELECTRICAL COMPONENTS “The Fiydw-mati 4L.60-£ transmission incorporates electronic con trols that uilize a Powertain Contol Mevule (PCM). The PCM gathers vehile opcrating information from a varity of sensor: Endcontal components lated throughout the powerin (engine and wansmision). The PCM processes this information fr proper ontol ofthe following: + transmission shi points through the shit solenoids, + Tomine Fol by adjusting ie prosareth the prea ‘onto solenoid + TCC aly and release timing - though the TCC solenoid, and 1 WeS-PAowmi= tough the ple width mote 3 con Electronic contro ofthese transmission operating characteristics prone fr Conia nd pres i out ands aly sed onthe operating conditions of both the engine and transmis FAIL-SAFE MODE “Faiv-safe” mode is an operating condition when the transmission srl partially function fs portion ofthe leeronie contol spe fsabled.” For example, if the wiring hamess Become disable, the PCM commands the fail-safe mode Which eases the tectonic solenoids to default to OFF. ‘The following changes ‘coc when the transmission is operating in the fail-safe mode + the pressure control solenoid is OFF, increasing line pressure 1 ¢ magima fo prevent any lute or bn siopae + the TCC slemi s OFF, preverting convener + the 3.2 control solenoid is OFF, providing faster 3-2 downshift and * both shit solenoids are OFF. With both shift solenoids OFF, the transmission will operate in ‘Thitd gear when the selector lever is in the Overdrive position, However, with the Hydra-matie 4L60-E transmission the driver has some Tlexibility in gear selection during fail-safe mode. Chang- ing gears during fail-safe mode is accomplished by moving the ‘gear seloctor lever as follows: Gear Selector Lever Position ‘Transmission Gear Operation Overdrive Range (©) “Third gear Drive Range (D) Third gear Manual Second (2) Second gear Manual First (1) Second gear Reverso (R) Reverse Park, Neutral (P2N) Park, Neutral ‘The downshift to First gear in Manual First is controlled electron cally for safety and durability reasons. ‘This means that the PCM ‘must electronically command both shift solenoids to be ON to Obtain Fist gear NOTE: This section of the book contains “general” information ‘about electrical components that provide input information to the PCM. Since some ofthis input information varies between vehicle ‘application, itis important that the appropriate General Motors Service Manual is used during repair of diagnosis of the transmis INPUTS, oo w a7 OUTPUTS INFORMATION SENSORS 1. VEHICLE SPEED SENSOR 2. TRANSMISSION FLUID TEMPERATURE SENSOR 3: FLUID PRESSURE SINTON ASSEMBLY (SA) 4. THROTTLE POSIDON SENSOR (TFS) 5. ENGINE SFEED SENSOR {6 ENGINE COOLANT TEMPERATURE SENSOR 1. BRAKE swe 4.4 WHEL OVE Low swToH |. AR CONOTIONING REQUEST ‘WLCRUSE CONTROL INFORMATION ‘T.MANIFOLD ABSOLUTE PRESSURE SENSOR ELECTRONIC CONTROLLERS «© POWERTRAIN CONTROL MCDULE PCM) ELECTRONICALLY CONTROLLED ‘TRANSMISSION COMPONENTS [A PRESSURE CONTROL SOLENOID 1. TORQUE CONVERTER CLUTCH SOLENOD SFT SOLENOID "A" (1-28-4SHFT) D. SHFTSOLENOD "8" @-3 SHIFT) E-2 CONTROL SOLENOD Figure 31ELECTRICAL COMPONENTS eu [ i etree mah oo ME 5 Io %6 9) = g e " ee en ae \ ale ons Pane | — OL PRESSE mvesroa) Rep oe [os [o> TO PARE REVERSE NEUTRAL 2 ior pressure Present ‘TRANSMISSION FLUID PRESSURE ‘swirc ‘ASSEMELY Co) IO) REVERSE INDICATOR ‘Switch NORMALLY CLOSED TRS CRECTOR PHA [Pn a o o 0 1 1 Pa PRESSURE SWITCH ASSEMBLY The transmission fluid Pressure Switch Assembly (PSA) is attached to the valve body and is used 10 Signal the manual valve position to the PCM. Various ‘uids ate routed to the PSA depending on the manual valve position. These Muids open and close the Muid presare switches in the PSA ta provide a signal ta the PCM indicating the gear range position of the manual valve. The combination of opened and closed switches determines the voltage measured at each of the three pins in the PSA electrical connector. An open circuit ‘measures 12 volts while a grounded circuit measures 0 volts. The electrical schematic and chart below show the PSA circuitry used to signal the manual valve Position Normally Open Fluid Pressure Switch The D4, Lo, and Reverse fluid pressure switches are ‘normally open and elcetical current is stopped at these switches when no fluid pressure is present, Fluid pres- sure moves the diaphragm and contact element uotit the contact element touches both the positive contact (and the ground contact (+), This cteates a closed circuit and allows current to flow from the positive contact, through the switch and to grou Normally Closed Fluid Pressure Switch The D2 and D3 fluid pressure switches are normally closed and electrical cur- rent is free low from the positive ‘contact tothe ground contact when no fluid pressure is present. Fluid pres- sure moves the diaphragm to discon- rect the positive and ground contacts. ‘This opens the switeh and stops cur- rent from flowing through the s Example ‘The hydraulic and electrical schemat- ies below are shown in the Drive Range (Manual Third) position (D or 3). D4 Muid pressure closes the D4 ‘uid pressure switch and D3 fluid pressure opens the D3 fluid pressure switch, With the D2 switch normally closed, pins N and P measure 0 volts while pin R measures approximately volts, This combination signals the PCM that the manual valve is in the Manual Third position wo ‘SYITCH LOGIE (NO) NORMALLY OPEN EXAMPLE: MANLAL THIRD (0) Figure 32ELECTRICAL COMPONENTS cae ELECTRICAL CONNECTOR VEHICLE SPEED SENSOR Low SPEED HIGH SPEED ourPur vouts TIME FiGuRE \: CONDITIONED SIGNAL, VEHICLE SPEED SENSOR (VSS) ‘The vehicle speed sensor is a magnetic inductive pickup that relays information relative to vehicle speed to the PCM. In the VSS is located on ission extension housing (31), opposite the speed sensor rotor. The speed sensor rotor is attached 10 the transmission output shaft and rotates with the output shaft at transmission output speed. The speed sensor rotor has 40) serrations, or teeth, cut into it’s outside diameter. ‘The VSS consists of a permanent magnet surrounded by a coil of wire. As the output shaft and speed sensor rotor rotate, an alternating current (AC) is indueed in the coil of ‘wire from the teeth on the rotor passing by the magnetic, pickup on the VSS. Whenever the vehicle is moving the VSS produces an AC voltage proportional to vehicle speed. This AC signal is sent to the digital ratio adaptor converter (DRAG) where itis converted to a direct current (DC) square wave form. ‘The DC signal is then sent to the PCM and interpreted as vehicle speed. As vehicle speed increases and. ‘more rotor teeth pass by the magnetic pickup on the VSS in a given time frame, the frequency of the DC signal sent 1 the PCM increases, The PCM interprets this increase in Frequency as an increase in vehicle speed (see Figure A). Note: On four wheel drive (4WD) applications the VSS is located on the transfer case. CONNECTOR RESISTOR Ojo ° (O) OO 10) eansassion |'O Ee) FLUID 2 PRESSURE ‘SWITCH ‘ASSEMBLY 69) ‘TEMPERATURE SENSOR ‘SENSOR RESISTANCE VS. TEMPERATURE gzesea eyes Sensor Resistance (K ohms) 3 ‘Temperature °C ‘TRANSMISSION FLUID TEMPERATURE SENSOR ‘The temperature sensor is a negative temperature coefficient, thermistor (Lemperature sensitive resistor) that provides information to the PCM regarding transmission fluid temperature. The temperature sensor isa part ofthe pressure switeh assembly (PSA) which is attached to the valve body dnd submersed in fuid in the transmission bottom pan. The internal electrical resistance of the sensor varies in relation to the operating temperature of the transmission fluid (see char). The PCM sends a 5 volt reference signal to the Temperature sensor and measures the voltage drop in the circuit. A lower fluid temperature creates a higher resistance inthe temperature sensor, thereby measuring higher volisge signal ‘The PCM measures this voltage as another input to help control TCC apply and line pressure. The PCM inhibits TCC apply until wansmission fluid temperature reaches: approximately 29°C (84°F). Also, when fluid temperatures exceed 135°C (275°F), the PCM commands TCC apply at all times in Fourth gear, as opposed to having a scheduled apply. Applying the TCC reduces fluid temperatures created, by the fluid coupling in the converter. Figure 33