928F WHEEL LOADER 2XL00001-01299 (MACHINE) POWERED BY 3116 ENGINE...

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Product: WHEEL LOADER

Model: 928F WHEEL LOADER 2XL00895
Configuration: 928F WHEEL LOADER 2XL00001-01299 (MACHINE) POWERED BY 3116 ENGINE

Testing and Adjusting

928F WHEEL LOADER POWER TRAIN
Media Number -SENR5994-00 Publication Date -01/06/1993 Date Updated -12/10/2001

Testing And Adjusting

Introduction
Reference: For Specifications with illustrations, refer to SENR5993, 928F Wheel Loader Power
Train. If the Specifications in SENR5993 are not the same as listed in the Systems Operation and the
Testing And Adjusting, look at the print date on the cover of each module.

Use the Specifications listed in the module with the latest date.

Troubleshooting
Troubleshooting the Transmission Hydraulic System
Make reference to the following warning and pressure tap locations for all checks and tests of the
transmission hydraulic system. If the problem area is not known, perform the checks and tests in the
order they are given. For all tests, the oil must be at normal temperature of operation.

Sudden movement of the machine or release of oil under pressure can

cause injury to persons on or near the machine. To prevent possible
injury, perform the procedure that follows before testing and adjusting
the transmission and power train. When testing and adjusting the
transmission and power train, move the machine to an area clear of
obstructions, with ventilation for the exhaust.

1. Move the machine to a smooth horizontal location. Move away from working machines and
personnel.
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2. Put the transmission FORWARD/REVERSE control lever in the NEUTRAL position and any
speed position. Stop the engine.

3. Put blocks in front of and behind the wheels.

4. Permit only one operator on the machine. Keep all other personnel either away from the machine or
in view of the operator.

5. Engage the parking brakes.

6. Lower the bucket or attachments to the ground.

7. Install steering frame lock link.

8. Make sure all hydraulic pressure is released before any fitting, hose or component is loosened,
tightened, removed or adjusted.

Troubleshooting can be complex. A list of some possible problems and corrections is on the pages
that follow.

This list of some possible problems and their corrections will only give an indication of where a
problem may be and what repairs are needed. Normally, more or other repair work is needed beyond
the recommendations on the list. Remember that a problem is not necessarily caused only by one part,
but by the relation of one part with other parts. This list cannot give all possible problems and
corrections. The service personnel must find the problem and its source, then make the necessary
repairs.

Always make visual checks first. Check the operation of the machine and then check with
instruments.

Visual Checks For The Transmission Hydraulic System

Make reference to the WARNING in the previous section

TROUBLESHOOTING THE TRANSMISSION HYDRAULIC
SYSTEM.

NOTE: If the machine will not move, check the transmission shifter fuse located on the right side
console. If the machine is equipped with the attachment AUTOSHIFT, also check the autoshift fuse
on the right side console.

Perform Visual Checks first when troubleshooting a problem. Make the checks with the engine
stopped and the parking brake engaged. Put the transmission shift control lever in NEUTRAL. During

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these checks, if necessary, use a magnet to separate ferrous (iron) particles from non-ferrous particles
(o-ring seals, aluminum, bronze, etc.).

Check 1:
Check the oil level in the front and rear differentials.

Check 2:
Check the oil level in transmission sump. Look for air or water in the oil. Many problems in the
transmission are caused by low oil level or air in the oil. Add oil to the transmission oil sump if it is
needed. See Operation & Maintenance Manual for recommended oil grade and viscosity.

a. Air (bubbles) may be caused by a loose or damaged fitting that allows air to enter the suction
side of the system along with allowing oil to leak out. Air may also be the result of gears
agitating oil in the sump if the transmission oil level is too high (overfill).
b. Coolant in the oil can be caused by a leaking transmission oil cooler. Water may enter the
system if the filler cap or dipstick is not properly installed.

Check 3:
Inspect all oil lines, hoses, and connections for damage or leaks. Look for oil on the ground under the
machine.

NOTE: If oil can leak out of a fitting or connection, air can leak in. Air in the system can be as
harmful as not enough oil.

Check 4:
Remove the drain plug in the bottom of the transmission case. This will drain all of the oil out of the
transmission. Remove and clean suction screen. Inspect the oil and suction screen for foreign
material. Remove and inspect (cut apart if necessary) the transmission oil filter for foreign material.

NOTE: There is an oil filter bypass valve on the inlet side of the transmission oil filter. The oil filter
bypass will open and allow oil to bypass the oil filter element whenever the pressure difference
between inlet oil and outlet oil through the oil filter is above 248 ± 21 kPa (36 ± 3 psi). Any oil that
does not flow through the filter element flows directly into the hydraulic control circuit. This dirty oil
may cause restrictions in valve orifices, sticking valves, etc.

a. Rubber particles indicate seal or hose failure.

b. Shiny steel particles indicate mechanical failure or gear wear of the transmission or pump.
c. A heavy accumulation of fibrous material indicates worn clutch discs in the transmission.
d. Aluminum particles indicate torque converter wear or failure, clutch piston wear, or worn
control valve body, selector spools, or load piston in the transmission control valve.
e. Iron or steel chips indicate broken components in transmission.

NOTE: If any of the above particles are found during any visual check, all components of the
transmission hydraulic system must be cleaned. Do not use any damaged parts. Any damaged parts
must be removed and new parts installed.

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Check 5:
The drive shaft(s) and universal joints must be free to rotate except when cold oil causes a resistance.
If the shafts are not free to turn, disconnect them and see if the transmission will turn.

Transmission Hydraulic Schematic

Transmission Hydraulic System Schematic

(1) Flow control valve. (2) Transmission control valve. (3) Selector spool and slug (FORWARD HIGH). (4) No. 1
(FORWARD HIGH) solenoid. (5) Selector spool and slug (FORWARD LOW). (6) No. 2 (REVERSE) solenoid. (7)
Selector spool and slug (REVERSE). (8) No. 3 (FORWARD LOW) solenoid. (9) Check valve. (10) Screen orifice. (11)
Modulating relief valve. (12) Slug. (13) Differential valve. (14) Spring. (15) Valve spool. (16) Differential relief valve.

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(17) Spring. (18) Poppet. (19) Load piston springs. (20) Converter back flow check valve. (21) Load piston. (22)
Transmission oil filter. (23) Selector spool and slug (FIRST SPEED). (24) Dump valve. (25) Transmission oil pump. (26)
No. 4 (FIRST SPEED) solenoid. (27) Selector spool and slug (SECOND SPEED). (28) Selector spool and slug (THIRD
SPEED). (29) No. 6 (THIRD SPEED) solenoid. (30) No. 5 (SECOND SPEED) solenoid. (31) Torque converter inlet relief
valve. (32) Suction screen and magnet. (33) Transmission lubrication circuit. (34) Oil cooler. (35) Torque converter.

Operational Checks

Make reference to the WARNING on the first page of Testing And

Adjusting section.

Operate the machine in each direction and in all speeds. Note the noises that are not normal and find
their source. If the operation is not correct, refer to the following problems and possible causes.

Troubleshooting Index
Problem 1: The transmission does not operate in any speed or slips in all speeds.

Problem 2: Transmission gets hot.

Problem 3: Pump noise not normal.

Problem 4: Noise in the transmission that is not normal.

Problem 5: Transmission operates in FORWARD only.

Problem 6: Transmission operates in REVERSE and FOURTH SPEED FORWARD only.

Problem 7: Transmission operates in REVERSE and FIRST through THIRD SPEED FORWARD
only.

Problem 8: Transmission does not operate in FIRST SPEED FORWARD or REVERSE.

Problem 9: Transmission does not operate in SECOND SPEED FORWARD or REVERSE.

Problem 10: Transmission does not operate in THIRD SPEED FORWARD or REVERSE and
FOURTH SPEED FORWARD.

Problem 11: Transmission does not operate in FOURTH SPEED FORWARD but does operate in
THIRD SPEED FORWARD.

Problem 12: Low pressure at pressure taps for P1 (speed) and P2 (direction) clutches in all speeds and
directions.

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Problem 13: Low pressure at P2 clutch pressure tap in REVERSE speeds.

Problem 14: Low pressure at P2 clutch pressure tap in FORWARD speeds.

Problem 15: High pressure at pressure taps for P1 (speed) and P2 (direction) clutches in all speeds and
directions.

Problem 16: Pressure differential between P1 and P2 not correct.

Problem 17: Clutch engagement is sudden (rough shifts).

Problem 18: Clutch engagement is slow (slow shifts-all gears).

Problem 19: Clutch engagement is slow (slow shifts-all FORWARD gears or all REVERSE gears or
any one gear in both FORWARD and REVERSE).

Problem 20: Loss of power during or after a THIRD GEAR to FIRST GEAR shift.

Problem 21: Transmission stays engaged when the neutralizer is actuated.

Problem 22: Transmission engages but the machine does not move and the engine lugs down.

Problem 23: With the engine running and the parking brake ENGAGED, the alarm does not sound
when the transmission selection lever is put into either a FORWARD or REVERSE direction.

Problem 24: Backup alarm does not sound when selection lever is put in REVERSE.

Problem 25: Low stall speed.

Problem 26: High stall speed in both directions.

Problem 27: High stall speed in one speed or in one direction.

Problem 28: Low lubrication pressure.

Problem 29: High lubrication pressure.

Problem 30: High converter pressure.

Problem 31: Low converter pressure.

Problem 32: Torque converter gets hot.

Problem 33: Constant noise in the differential.

Problem 34: Noise at different intervals.

Problem 35: Noise on turns only.

Problem 36: Leakage of lubricant.

Problem 37: Drive wheels do not turn (universal joint turns).

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Troubleshooting
NOTE: In the following troubleshooting, for numbers in parenthesis, refer back to the schematic.

NOTE: If the machine is equipped with the attachment AUTOSHIFT, some electrical diagnostics are
performed by the Autoshift Control. See SENR5751, Electronic Transmission Control for diagnostic
procedures.

Problem 1: The transmission does not operate in any speed or slips in all speeds.

Possible Causes:

1. Transmission shifter fuse is open or blown.

2. Problem in the electrical circuit (see Electrical Tests).
3. Low system voltage.
4. Transmission shift control unit (shift lever) is defective.
5. Low oil pressure caused by:

a. Low oil level.

b. Restriction in the oil flow circuit such as a dirty oil strainer.
c. Oil pump failure.
d. Air leaks on the inlet side of the pump.
e. Leakage inside the transmission:

Worn or damaged seal rings on the clutch shaft.

Worn or damaged seals around the clutch piston.

f. Modulating relief valve (11) stuck open.

6. Torque converter failure.

7. Mechanical failure in the transmission.
8. Clutch discs and plates are worn too much.
9. Transmission neutralizer switch is inoperative.
10. Check valve (9) stuck open.

Problem 2: Transmission gets hot.

Possible Causes:

1. Low coolant level in the engine radiator.

2. Wrong application for the vehicle. There is too much torque converter slippage caused by too
much load.
3. Incorrect transmission gear for load on machine. Shift to a lower gear.
4. Defective temperature gauge.
5. Incorrect (high or low) oil level.
6. Oil cooler or lines are restricted.
7. Clutch slips too much.

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a. Low oil pressure. See Problem: Transmission does not operate in any speed or slips in
all speeds.
b. Damaged clutch.

8. Low oil flow caused by pump wear or leakage in the hydraulic system.
9. Air mixed in the oil. Air leaks on the intake side of the pump.
10. Torque converter inlet relief valve (31) is stuck open, which causes low oil flow through the
torque converter.
11. Clutch or clutches not fully released (drag).

a. Warped plates or discs.

b. Broken or weak return spring.

Problem 3: Pump noise not normal.

Possible Causes:

1. A loud sound at short time periods indicates that foreign material is in the transmission
hydraulic system.
2. A constant loud noise indicates pump failure.
3. Air at the inlet side of the pump.

Problem 4: Noise in the transmission that is not normal.

Possible Causes:

Transmission components are worn or damaged:

a. Damaged gears.
b. Worn teeth of clutch plates and/or clutch discs.
c. Slipping clutch plates and disc noise.
d. Other component parts that are worn or damaged.

Problem 5: Transmission operates in FORWARD only.

Possible Causes:

1. Transmission REVERSE solenoid valve (6) is inoperative (see Solenoid Test).

2. Problem in the electrical circuit (see Electrical Tests).
3. REVERSE clutch not engaged (slips) because of:

a. Low oil pressure because of leaking seals on piston or shaft.

b. Discs and plates have too much wear.
c. Broken components.

4. Selector spool (7) is stuck.

Problem 6: Transmission operates in REVERSE and FOURTH SPEED FORWARD only.

Possible Causes:

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1. Transmission FORWARD LOW solenoid valve (8) is inoperative (see Solenoid Test).
2. Problem in the electrical circuit (see Electrical Tests).
3. FORWARD LOW clutch not engaged (slips) because of:

a. Low oil pressure because of leaking seals on piston or shaft.

b. Discs and plates have too much wear.
c. Broken components.

4. Selector spool (5) is stuck.

Problem 7: Transmission operates in REVERSE and FIRST through THIRD SPEED

FORWARD only.

Possible Causes:

1. Transmission FORWARD HIGH solenoid valve (4) is inoperative (see Solenoid Test).
2. Problem in the electrical circuit (see Electrical Tests).
3. FORWARD HIGH clutch not engaged (slips) because of:

a. Low oil pressure because of leaking seals on piston or shaft.

b. Discs and plates have too much wear.
c. Broken components.

4. Selector spool (3) is stuck.

Problem 8: Transmission does not operate in FIRST SPEED FORWARD or REVERSE.

Possible Causes:

1. FIRST SPEED solenoid valve (26) is inoperative (see Solenoid Test).

2. Problem in the electrical circuit (see Electrical Tests).
3. FIRST SPEED clutch not engaged (slips) because of:

a. Low oil pressure because of leaking seals on piston or shaft.

b. Discs and plates have too much wear.
c. Broken components.

4. Selector spool (23) stuck.

Problem 9: Transmission does not operate in SECOND SPEED FORWARD or REVERSE.

Possible Causes:

1. SECOND SPEED solenoid (30) is inoperative (see Solenoid Test).

2. Problem in the electrical circuit (see Electrical Tests).
3. SECOND SPEED clutch not engaged (slips) because of:

a. Low oil pressure because of leaking seals on piston or shaft.

b. Discs and plates have too much wear.
c. Broken components.

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4. Selector spool (27) stuck.

Problem 10: Transmission does not operate in THIRD SPEED FORWARD or REVERSE and
FOURTH SPEED FORWARD.

Possible Causes:

1. THIRD SPEED solenoid (29) is inoperative (see Solenoid Test).

2. Problem in the electrical circuit (see Electrical Tests).
3. THIRD SPEED clutch not engaged (slips) because of:

a. Low oil pressure because of leaking seals on piston or shaft.

b. Discs and plates have too much wear.
c. Broken components.

4. Selector spool (28) stuck.

Problem 11: Transmission does not operate in FOURTH SPEED FORWARD but does operate
in THIRD SPEED FORWARD.

Possible Causes:

1. Transmission FORWARD HIGH solenoid valve (4) is inoperative (see Solenoid Test).
2. Problem in the electrical circuit (see Electrical Tests).
3. FORWARD HIGH clutch not engaged (slips) because of:

a. Low oil pressure because of leaking seals on piston or shaft.

b. Discs and plates have too much wear.
c. Broken components.

4. Selector spool (3) is stuck.

Problem 12: Low pressure at pressure taps for P1 (speed) and P2 (direction) clutches in all
speeds and directions.

Possible Causes:

1. Modulating relief valve (11) stuck.

2. Low oil pressure. See Problem: Transmission does not operate in any speed or slips in all
speeds.
3. Load piston springs (19) weak, damaged, or missing.
4. Dump valve (24) stuck open.
5. Flow control valve (1) stuck open.
6. Check valve (9) stuck open.

Problem 13: Low pressure at P2 clutch pressure tap in REVERSE speeds.

Possible Causes:

Too much leakage in the REVERSE clutch piston or shaft seals.

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Problem 14: Low pressure at P2 clutch pressure tap in FORWARD speeds.

Possible Causes:

Too much leakage in the FORWARD clutch piston or shaft seals.

Problem 15: High pressure at pressure taps for P1 (speed) and P2 (direction) clutches in all
speeds and directions.

Possible Causes:

1. Operation of modulating relief valve (11) sticky.

2. Load piston (21) stuck.
3. Wrong load piston springs (19).
4. Worn slug (12) or worn modulating relief valve (11) bore.

Problem 16: Pressure differential between P1 and P2 not correct.

Possible Causes:

1. Operation of pressure differential valve (13) not correct.

a. Weak or damaged spring (14).

b. Wrong spring (14).
c. Faulty valve spool (15).

2. Operation of differential relief valve (16) not correct.

a. Weak or damaged spring (17).

b. Wrong spring (17).
c. Faulty poppet (18).

3. Flow control valve (1) stuck closed.

Problem 17: Clutch engagement is sudden (rough shifts).

Possible Causes:

1. Operation of pressure differential valve (13) not correct.

a. Weak or damaged spring (14).

b. Wrong spring (14).
c. Faulty valve spool (15).

2. Operation of differential relief valve (16) not correct.

a. Weak or damaged spring (17).

b. Wrong spring (17).
c. Faulty poppet (18).

3. Load piston (21) stuck.

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4. Load piston springs (19) are wrong or damaged.

5. Dump valve (24) stuck closed.
6. Back flow check valve (20) not seating or missing.

Problem 18: Clutch engagement is slow (slow shifts-all gears).

Possible Causes:

1. Check valve (9) for the load piston is not closing (open to drain) or screen orifice (10) for the
load piston is dirty (plugged).
2. Low oil pressure. See Problem: Transmission does not operate in any speed or slips in all
speeds.
3. Load piston springs (19) are weak or have damage.
4. Modulating relief valve (11) is stuck.

Problem 19: Clutch engagement is slow (slow shifts-all FORWARD gears or all REVERSE
gears or any one gear in both FORWARD and REVERSE).

Possible Causes:

Low clutch pressure because of leaking seals on the piston or shaft for the affected gear.

Problem 20: Loss of power during or after a THIRD GEAR to FIRST GEAR shift.

Possible Causes:

Two clutches wrongly engaged because the return spring for selector spool (28) is broken or missing.

Problem 21: Transmission stays engaged when the left brake pedal is pushed.

Possible Causes:

1. Transmission neutralizer switch out of adjustment.

2. Failure in transmission neutralizer switch.
3. Transmission control group (lever) problem.

Problem 22: Transmission engages but the machine does not move and the engine lugs down.

Possible Causes:

1. Machine brakes are locked up.

2. Parking brake not released or locked up.
3. Mechanical failure in a differential (front or rear).
4. Mechanical failure in a final drive.
5. Mechanical failure in the transmission.

Problem 23: With the engine running and the parking brake ENGAGED, the alarm does not
sound when transmission selection lever is put into either a FORWARD or REVERSE
direction.

Possible Causes:

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1. Failure of the alarm.

2. Failure in the wiring.

a. Loose or defective connector.

b. Broken wire.

Problem 24: Backup alarm does not sound when selection lever is put in REVERSE.

Possible Causes:

1. Failure of backup alarm fuse.

2. Failure of backup alarm.
3. Failure in the wiring

a. Loose or defective connector.

b. Broken wire.

4. Transmission control group (lever) problem.

Problem 25: Low stall speed.

Possible Causes:

1. Engine performance is not correct.

2. Cold oil.

Problem 26: High stall speed in both directions.

Possible Causes:

1. Low oil level.

2. Air in the oil.
3. Clutches are slipping.
4. Torque converter failure.

Problem 27: High stall speed in one speed or in one direction.

Possible Causes:

1. There is a leak in the clutch circuit.

2. There is a clutch failure in the speed or direction that there is high stall speed.

Problem 28: Low lubrication pressure.

Possible Causes:

1. Converter inlet relief valve (31) passing flow (see High Converter Pressure and Low
Converter Pressure).
2. Low pump flow or pressure. See Problem: Transmission does not operate in any speed or
slips in all speeds.

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Problem 29: High lubrication pressure.

Possible Causes:

Blocked lube holes in clutch shaft.

Problem 30: High converter pressure.

Possible Causes:

1. A restriction inside the converter.

2. A restricted oil passage or oil cooler.

Problem 31: Low converter pressure.

Possible Causes:

1. Converter inlet relief valve (31) is stuck open.

2. Low pump flow or pressure. See Problem: Transmission does not operate in any speed or
slips in all speeds.

Problem 32: Torque converter gets hot.

Possible Causes:

1. Wrong application for the vehicle. There is too much torque converter slippage caused by too
much load.
2. Incorrect transmission gear for load on machine. Shift to a lower gear.
3. Incorrect (high or low) oil level in the transmission.
4. Low water level in the engine radiator.
5. Restrictions in the oil cooler or lines.
6. Not enough oil to the converter because of:

a. Converter inlet relief valve (31) bypassing too much flow.

b. Low pump flow or pressure. See Problem: Transmission does not operate in any speed
or slips in all speeds.

Problem 33: Constant noise in the differential.

Possible Causes:

1. Lubricant above or below the proper level.

2. Wrong type of lubricant.
3. Wheel bearings are out of adjustment or are defective.
4. The ring gear and pinion do not have correct tooth contact.
5. The ring gear and pinion are damaged or worn.
6. There is too much or too little pinion to gear backlash.
7. Loose or worn pinion bearings.
8. Loose or worn side bearings.

Problem 34: Noise at different intervals.

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Possible Causes:

1. Ring gear does not run even:

a. Bolts on the ring gear are not tight.

b. The ring gear is warped.

2. Loose or broken differential bearings.

Problem 35: Noise on turns only.

Possible Causes:

1. The differential pinion gears are too tight on the retainer pins or the pinion shaft.
2. Side gears are too tight in the differential case.
3. Differential pinion or side gears are defective.
4. Thrust washers are worn or damaged.
5. Too much backlash between the side and pinion gears.

Problem 36: Leakage of lubricant.

Possible Causes:

1. Loss through axle shafts:

a. Lubricant above the proper level.

b. Wrong type of lubricant.
c. Axle housing breather is restricted.
d. Axle shaft oil seal is installed wrong or is damaged.

2. Loss at pinion shaft:

a. Lubricant above the proper level.

b. Wrong type of lubricant.
c. Axle housing breather is restricted.
d. Pinion oil seal worn or is not installed correctly.
e. Universal joint flange loose on the pinion shaft.

Problem 37: Drive wheels do not turn (universal joint turns).

Possible Causes:

1. Broken axle shaft.

2. Ring gear teeth are damaged.
3. Side gear or differential pinion are broken.
4. Differential pinion shaft or retainer pin are broken.

Transmission Hydraulic Tests

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Make reference to the WARNING on the first page of Testing And

Adjusting section.

Transmission Pump
Specifications For Bench Test

Type ... Gear

Number of sections ... One

Rotation ... Counterclockwise

Output (minimum) [using SAE 10W oil at 49°C (120°F)] ... 90.5 liter/min (24 U.S. gpm)

Based on speed of ... 1800 rpm

When developing pressure of ... 2750 kPa (400 psi)

Pressure Tap Location

Many of the pressure taps for testing the power train hydraulic system have quick disconnect nipples
already installed.

Do not connect or disconnect hose fittings to or from the nipples when there is pressure in the system.
This will prevent damage to the seals that are in the fitting.

Pressure Tap Location

(A) Direction clutch [P2]. (B) Speed clutch [P1]. (C) Torque Converter Inlet [P3].

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Pressure Tap Location

(D) Transmission lubrication.

Pressure Tap Location

(E) Torque Converter Outlet.

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Torque Converter Stall Test

The converter stall test is a test of the engine, torque converter, drive train, and brake system as a unit.
The converter output is stalled while the engine is operated at full throttle. This test will give an
indication, by the speed the engine reaches, whether the engine and transmission performance is
acceptable (satisfactory) under full load. A lower or higher speed than that given as normal are
indications of either engine or transmission problems. If the engine performance is correct, and the
stall speed is not correct, the problem is in the converter or transmission.

NOTE: To check the engine performance, see Service Manual Modules SENR3582, SENR3583, and
SENR4615 for information on the Caterpillar 3116 Engine.

The drive wheels must not turn during the stall test. Put the machine in position against a solid object
(if available), that will not move (such as a loading dock). Engage the parking brake. When tests are
made, the service brakes must be applied. Make sure the transmission oil is at normal temperature for
operation, 82 to 93°C (180 to 200°F).

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To help prevent personal injury, Perform tests in a clean level area only
and with ventilation for the exhaust. There must be only one operator.
Keep all other personnel away from the machine. Check the operation
of the brakes before the tests are made.

1. Install the 6V3121 Multitach Group on the engine.

2. Apply the service brakes and start the engine.

NOTICE

To make sure that the transmission oil does not get too hot, do not keep
the torque converter in a full stall condition for more than 30 seconds.
After the torque converter is stalled, put the control in NEUTRAL and
run the engine at 1200 to 1500 rpm to cool the oil.

3. Put the transmission control lever in FOURTH SPEED FORWARD. Push the accelerator pedal
down completely. Allow the engine rpm to stabilize and take a reading from the tachometer.

4. The correct stall speed is 2090 ± 65 rpm.

Stall speeds that are low are an indication that engine performance is not correct. If the test is to be
repeated, allow at least two minutes between tests with the transmission in NEUTRAL.

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Electrical Tests

Transmission Electrical Schematic

(1) Connector at rear of transmission.

(2) Ten pin connector.

(3) Eight pin connector.

For a complete electrical schematic of the 928F, see SENR5969, 928F Wheel Loader Electrical
System Schematic.

If the wire harness connections are not made properly, they can cause either continuous or intermittent
problems. Make sure all connectors in a problem circuit are fastened correctly before tests are
performed.

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Input Voltage To Shift Control

NOTE: Repair wiring after probing. Seal the punctures with 8T0065 Adhesive. Cover the adhesive
with two layers of 1P0810 Tape.

DO NOT DISCONNECT ANY HARNESS CONNECTORS AT THIS TIME.

Turn the key switch to the ON position. DO NOT START THE ENGINE.

To test for voltage, use sharp meter test leads, puncture the wire insulation and measure the voltage
between contacts.

Input voltage to the shift control can be checked between contacts 1 and 9. The voltage measured
should be equal to the machine system voltage. If no voltage is measured, check all harness
connectors and the supply fuse.

Shift Control Solenoid Circuit Tests

The chart gives the contact numbers across which a voltage measurement should be taken when the
gear selector is in the gear shown.

NOTE: Repair wiring after probing. Seal the punctures with 8T0065 Adhesive. Cover the adhesive
with two layers of 1P0810 Tape.

DO NOT DISCONNECT ANY HARNESS CONNECTORS AT THIS TIME. Turn the key switch to
the ON position. DO NOT START THE ENGINE.

To test for voltage, use sharp meter test leads, puncture the wire insulation and measure the voltage
between contacts.

Additional Checks
These checks are to be performed at the eight pin connector coming from the shift control.

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Neutral Start
Perform this test with the engine stopped and the key switch in the OFF position.

With the shift control lever in NEUTRAL, there must be continuity between contacts 3 and 4. This
indicates the ability to start the machine. If there is no continuity, the machine will not start and the
shift control must be replaced.

Back-Up Alarm
Perform this test with the engine stopped and the key switch in the OFF position.

With the shift control lever in REVERSE, there must be continuity between contacts 2 and 5. This
activates the back-up alarm. If there is no continuity, the back-up alarm will not work and the shift
control must be replaced.

Transmission Neutralizer
Perform this test with the engine stopped and the key switch in the ON position.

Put the transmission neutralizer lock out switch in the OFF position (bottom of switch depressed,
lamp off). With the service brake NOT applied, there must be voltage measured between contacts 1
and 2. If there is no voltage, check all harness connectors and the transmission neutralizer switch at
the brake pedal.

Depress either service brake pedal. There must not be voltage between contacts 1 and 2. If there is
voltage, check the transmission neutralizer switch at the brake pedal.

With service brake pedal still depressed, move the transmission neutralizer lockout switch to the ON
position (top of switch depressed, lamp on). There must now be voltage between contacts 1 and 2. If
there is no voltage, check all harness connections and the transmission neutralizer lockout switch.

Solenoid Test
This test will determine if the electrical coil is energizing and the plunger is shifting to permit oil
flow.

Hearing a solenoid click or checking to see if the coil is energized by checking magnetically with a
screw driver does not insure the solenoid plunger has shifted. The following test will tell if the
solenoid plunger is shifting.

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Solenoid Valve Location

(1) No. 1 (FORWARD HIGH) solenoid. (2) No. 2 (REVERSE) solenoid. (3) No. 3 (FORWARD LOW) solenoid. (4) No.
4 (FIRST SPEED) solenoid. (5) No. 5 (SECOND SPEED) solenoid. (6) No. 6 (THIRD SPEED) solenoid.

Make reference to the WARNING on the first page of Testing And

Adjusting section.

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1. Install a 0-4000 kPa (0-600 psi) gauge and hose on P2 pressure tap.

2. Engage the parking brake and start the engine. Run the engine at LOW IDLE.

3. Move the transmission neutralizer lockout switch to the ON position (bottom of switch depressed,
lamp on).

4. Depress and hold the brake pedal. While watching the pressure gauge, move the shift lever from
NEUTRAL to FORWARD. The needle on the pressure gauge should drop and then return to the
original pressure. Shift through all FORWARD speeds. The same pressure drop should be noted in all
speeds.

5. Perform Step 4 for all REVERSE speeds. The pressure drop should be noted in all REVERSE
speeds.

If the pressure drop can be seen, the solenoid and it's related electrical circuit is functioning.

If the pressure drop can not be seen, check to see if the solenoid coil is energized with a screwdriver.
If the screwdriver indicates that the coil is energized, the problem is in the solenoid cartridge. The
problem could be a bent stem, dirty or clogged screen, or a weak or broken spring.

NOTE: If the solenoid cartridge rattles when shaken, it is no good. The spring which seats the
plunger is weak or broken.

If the screwdriver does not indicate that the coil is energized, the problem is in the electrical circuit.
Possible problems include a bad solenoid coil, a bad connection in a connector, a broken wire, or a
faulty shift control group.

NoSPIN Differential

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NoSPIN Differential Test (Before Installation)

After the NoSPIN differential has been assembled and before it is installed in the machine, make a
test of the operation of the differential as follows:

1. Install the NoSPIN differential in the case.

2. Put the case in a stand or a vise to keep it from rotation.

3. Install both axles in the case.

Test Procedure For NoSPIN Differential

(1) Case. (A) Axle. (B) Axle.

4. Put a force in a clockwise direction on both axles.

5. Keep the force on axle (A) and turn axle (B) in a counterclockwise direction. A small noise will be
heard in the NoSPIN differential and axle (B) will turn freely.

NOTE: Make sure the force is kept on axle (A).

6. Keep the force on axle (A) and turn axle (B) in a clockwise direction. A small noise will be heard
in the NoSPIN differential and axle (B) will not turn any farther.

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NoSPIN Differential Test

7. Put a force in a counterclockwise direction on both axles.

8. Keep the force on axle (A) and turn axle (B) in a clockwise direction. A small noise will be heard
in the NoSPIN differential and axle (B) will turn freely.

NOTE: Make sure the force is kept on axle (A).

9. Keep the force on axle (A) and turn axle (B) in a counterclockwise direction. A small noise will be
heard in the NoSPIN differential and axle (B) will not turn any farther.

10. Perform Steps 4 through 9 again, except now hold axle (B) and turn axle (A).

If the NoSPIN differential does not have the correct action, inspect the components and check the
assembly procedure.

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All Rights Reserved.
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