DRIVE AXLE

1986 Isuzu Trooper II

1986 DRIVE AXLES

Isuzu

Impulse Turbo, P’UP & Trooper II

DESCRIPTION
Rear axle housing is banjo type with removable differential
carrier and semi-floating drive axles. Front axle has removable
differential carrier and full-floating drive axles.
Both differentials are hypoid type ring and pinion gears.
Drive axles are retained in housing by cone-type roller bearings and
bearing retainers at axle housing outer ends.

AXLE RATIO & IDENTIFICATION

All models are equipped with one type of rear axle. Front
axle on 4WD models is similar to rear axle. Gear ratio on 2WD
vehicles with manual transmission is 3.42:1 for gasoline model, and
3.73:1 for diesel model.
Gear ratio on automatics and 4WD vehicles front and rear is
4.10:1. Gear ratio for Trooper II is 4.56:1 for front and rear drive
axles. Gear ratio for Impulse turbo models is 3.91:1. Gear ratio is
determined by dividing number of ring gear teeth by number of drive
pinion gear teeth.

REMOVAL & INSTALLATION

NOTE: References to BJ refer to Birfield Joint; DOJ to Double
Offset Joint.

DRIVE AXLES & BEARINGS

NOTE: Front axle assembly must be removed prior to removal of
drive axles and bearings.

Removal (Front)
1) Raise front of vehicle and support frame on jack stands.
Remove wheels and skid plate. Mark drive shaft for reinstallation
and disconnect at front differential.
2) Completely loosen torsion bar by turning height control
arm adjusting bolts. Remove strut bars. Remove stabilizer
bar-to-lower control arm bolts and disconnect stabilizer.
3) Remove brake calipers from supports and hang on frame
with wire. Disconnect ball joints at outer tie rods. Remove upper
control arms from frame brackets by removing bolts from upper pivot
shafts.
4) Tape shim packs together and mark for reinstallation for
proper camber and caster adjustments. Remove lower control arm link
ends, shock absorber-to-lower control arm bolts and lower control
arms.
5) Move transfer shift lever into "2H" position and set
locking hub knob to "FREE" position. Remove locking hub assembly.
Remove snap ring and shims from end of spindle.
6) Remove hub and rotor assembly along with upper link and
front axle (both sides). Disconnect pitman arm and idler arm. Remove
steering linkage assembly.
NOTE: See LOCKING HUB article in this section for complete removal
and installation procedures of locking hubs.

7) Support front axle assembly on floor jack and remove 4

axle case mounting bolts. Lower and remove front axle assembly. DO
NOT damage Birfield Joints (BJ) or Double Offset Joints (DOJ).
8) Drain differential housing. Remove 4 axle mounting
bracket-to-axle housing bolts. Pull drive axles from both sides of
housing. Remove drive axle bearing from steering knuckle using a
puller. Drive out bearing races with brass drift and replace races
with hydraulic press. Install new bearings.

Installation
1) Install drive axles in housing and tighten 4 axle
retainer mounting bolts. Place front axle assembly on floor jack and
position under vehicle frame. Install axle assembly and tighten case
mounting bracket bolts.
2) Install Pitman arm to steering sector shaft and idler arm
to pivot shaft. Tighten bolts. Install hub and rotor assemblies with
upper control arms to drive axle ends. Install pivot shaft to frame
bracket.
3) Install camber and caster adjusting shims in original
positions. Refit shock absorbers. Connect lower control arms to frame
brackets. Connect ball joints to knuckle arms and tighten nuts.
4) Install strut bars and stabilizer bar ends. Tighten
control arm adjusting bolts. Install disc brake caliper assemblies.
Thoroughly lubricate locking hub body and lock washer. Install snap
ring.
5) Push drive axle with hand pressure and set clearance
between locking hub body and snap ring to .112" (3 mm) using required
shims. Install gasket and locking hub cover, aligning stopper rails
during installation.
6) Install wheels and skid plate. Align drive shaft
index marks and install drive shaft. Tighten all nuts and bolts
to specifications. Fill front differential with lubricant. Bleed
hydraulic brake system (if required).
Fig. 1: Exploded View of Isuzu Rear Axle Assembly
Courtesy of Isuzu Motor Co.

Removal (Rear) - Impulse

1) Raise and support vehicle. Remove wheel and tire
assembly. Remove and support caliper assembly. Do not disconnect
brake hose from caliper. Remove brake rotor.
2) Remove 4 bearing retainer plate bolts. Disconnect parking
brake cable. Remove axle shaft using a puller. Remove backing plate,
sleeve, bearing, bearing retainer and oil seal.

Removal (Rear) - Except Impulse

1) Raise vehicle. Remove wheel and tire assembly. Remove
brake drum and brake shoes, and disconnect parking brake inner cable.
Disconnect brake lines from wheel cylinders and plug end to prevent
loss of fluid and contamination.
2) From inboard side of brake backing plate, remove 4 nuts
from bearing holder through bolts. Pull drive axle from housing.
Fig. 2: Exploded View of Rear Axle Shaft Assembly
Courtesy of Isuzu Motor Co.

Bearing Replacement - Impulse

To replace axle bearing, press old bearing from axle shaft,
using Bearing Remover (J-33949). Install "O" ring in groove on
bearing outer race. Install bearing with "O" ring toward splined end
of axle shaft. Install sleeve, with flanged side facing bearing.
Press bearing and sleeve on axle shaft using a press and Bearing
Installer (J-22912-01).

Bearing Replacement - Except Impulse

1) To replace axle bearing, flatten locking tab of lock
washer, and mount drive axle in a vise, clamping vise jaws around
lock nut. Using Remover/Installer (J-24226) positioned on lug bolts,
turn drive axle to loosen lock nut.
2) Remove lock nut, lock washer, bearing, holder and brake
backing plate. Remove oil seal from outboard side of bearing holder.
Press off bearing holder and bearing. Drive off bearing outer race
with a brass drift.
3) Install bearing outer race and grease seal into holder.
Apply wheel bearing grease to bearing holder, rear axle tube and
bearing inner race. Insert 4 through bolts into backing plate.
Install bearing holder to backing plate. Ensure oil seal side of
bearing holder is against backing plate.
4) Place backing plate assembly over drive axle, position
bearing over drive axle and press into bearing holder. Install new
lock washer with dished side away from bearing. Thread lock nut onto
shaft.
5) Place lock nut between vise jaws and using tool used
during disassembly, tighten lock nut securely. Bend over portion of
lock washer opposite to locating tab to prevent lock nut from turning.
 Installation
1) If both drive axles were removed, insert a .079" (2 mm)
shim between bearing holder and axle tube flange of first drive axle
to be installed. Insert shaft into axle tube and install and tighten
bearing holder-to-flange bolts.
2) For the second drive axle (or if only one shaft was
removed), insert shaft without shims into axle tube until it comes
into contact with thrust block in differential. Measure clearance
between bearing holder and axle tube flange. See Fig. 3.

Fig. 3: Sectional View of Axle Shaft Bearing Assembly

Courtesy of Isuzu Motor Co.

3) Proper size shims for this location may be determined by

adding .012" (.3 mm) to measurement just obtained. Select a shim or
combination of shims, withdraw drive axle and install shims between
bearing holder and flange face.
4) Reinstall drive axle and tighten 4 through bolts. Connect
brake line to wheel cylinder. Install brake shoes, parking brake
cable and brake drum. Install wheel and tire assembly, adjust brakes
and bleed system.

DIFFERENTIAL CARRIER
NOTE: Front differential carrier is removed from front axle after
axle has been removed from vehicle.

Removal (Rear)
1) Raise rear of vehicle and support with jack stands.
Remove wheel and tire assemblies. On Impulse models, remove and
support calipers. Remove rotors. On all other models, remove brake
drums. Disconnect brake lines at wheel cylinders and plug.
2) On all models, disconnect parking brake cable brackets at
rear spring location. Drain differential oil. Remove 4 axle retainer
mounting bolts from each end flange and partially withdraw drive
axles from axle tubes.
3) Disconnect drive shaft from pinion flange and place
out of way. Remove nuts attaching carrier to axle housing and remove
carrier assembly.

Installation
To install, reverse removal procedure. Refill axle with
correct amount of lubricant.

OVERHAUL

DIFFERENTIAL ASSEMBLIES
NOTE: Overhaul procedures of front and rear differentials are
similar.

Disassembly
1) Mark side bearing caps for reassembly reference. Remove
side bearing caps. Remove differential case assembly. Remove
differential side bearings from case. Record thickness of each side
bearing and shim pack and place with appropriate bearing race.

Fig. 4: Exploded View of Front Differential Assembly

Courtesy of Isuzu Motor Co.

2) Remove ring gear bolts and separate ring gear from case.
Remove stakes retaining lock pin using .20" (5 mm) drill. Drive out
pinion shaft lock pin using a long drift. Check pinion gear-to-side
gear backlash before removal.
3) Backlash should be .001-.003" (.03-.08 mm). Remove pinion
shaft using a drift. Withdraw thrust block (if equipped), pinion
gears, side gears and thrust washers from carrier. It may be
necessary to remove stakes retaining lock pin using a 5 mm drill.
Fig. 5: Removing Pinion Shaft Lock Pin
Courtesy of Isuzu Motor Co.

4) Remove pinion nut and pinion flange using Flange Holder

(J-8614-01). Drive pinion gear from carrier using hammer and brass
drift. Withdraw front pinion bearing and oil seal.
5) Using a brass drift, remove pinion bearing inner and
outer races from carrier. Mount pinion gear in a press and remove
rear pinion bearing and depth shim from pinion gear.

Reassembly & Adjustment (Case Assembly)

1) Install side gears and thrust washers in case. Position
thrust washers 180 degrees apart, roll gears into position making
sure they are in alignment to allow installation of pinion shaft.
2) Place thrust block between pinion gears (if equipped).
Drive pinion shaft into position, ensuring lock pin hole aligns with
hole in case. Measure backlash between side gears and pinion gears;
if greater than .007" (.18 mm), install selective thrust washers to
bring backlash within specifications.
3) Thrust washers are available in thicknesses of .039" (.99
mm), .041" (1.04 mm), .043" (1.09 mm), .045" (1.14 mm), .047" (1.19
mm), .049" (1.24 mm), .051" (1.30 mm), .053" (1.35 mm) and .055"
(1.40 mm) for Impulse models and .039" (.99 mm), .041" (1.04 mm) and
.043" (1.09 mm) for P’UP and Trooper II models.

NOTE: Increasing thrust washer thickness decreases backlash;

decreasing thrust washer thickness increases backlash.

4) Install lock pin in pinion shaft and stake end to prevent

loosening. Install ring gear in position on case, apply Loctite to
threads and tighten bolts in diagonal sequence to 63 ft. lbs. (85
N.m) on Impulse models and 72-87 ft. lbs. (98-118 N.m) on rear
differential or 51-65 lbs. (69-88 N.m) on front differential on all
other models.

Reassembly & Adjustment (Drive Pinion Depth)

1) Install front and rear pinion bearing races into carrier
bores. Lubricate pinion bearings and position in respective races.
Install Gauge Plate (J-23597-7), Preload Stud (J-23597-9) and Pilot
(J-21777-42) through front and rear bearing and tighten nut securely.
2) Rotate bearing to ensure proper seating. Tighten pinion
lock nut to 8-10 ft. lbs. (10-12 N.m) for used bearings and 17 ft.
lbs. (23 N.m) for new bearings. Clean differential case bearing bores.

Fig. 6: Installing Pinion Height Gauge

Courtesy of Isuzu Motor Co.

3) Place Mounting Discs (J-23597-8) on Arbor (J-23597-1) and

place assembly in position in side bearing bores. Install bearing
caps snugly. Mount dial indicator on arbor post and preload dial
indicator 1/2 revolution. Tighten indicator in this position.
4) Position indicator plunger on gauge plate, slowly swing
across until highest reading is obtained, and "zero" indicator on
highest reading of gauge plate.
5) Carefully swing plunger off gauge plate and note
indicator reading. Reading is correct thickness of rear pinion depth
shim for a nominal drive pinion.

NOTE: Front differential pinion shims are available in sizes

ranging from .055-.070" (1.40-1.79 mm). Rear differential
pinion shims are available in sizes ranging from .055-.071"
(1.40-1.80 mm) on Impulse models and .086-.101" (2.18-2.56
mm) on all other models. A rear differential indicator
reading of 0 (zero) or .001" (.03 mm) requires shims of
.100" (2.54 mm) and .101" (2.56 mm) respectively.

Fig. 7: Pinion Depth Code Location on Pinion Head

Courtesy of Isuzu Motor Co.

6) Examine head of drive pinion. Pinion depth code is

stamped by chemical ink and is lower of 3 numbers. A "+" (plus)
number indicates need for greater mounting distance (decreased shim
thickness).
7) A "-" (minus) number indicates need for smaller mounting
distance (increased shim thickness). See PINION DEPTH SHIM CHART to
determine proper shim variation to compensate for plus or minus
markings.
8) If pinion depth code is "0", pinion is "nominal" and no
dial indicator correction is required. Using Bearing Installer
(J-6133-01), place selected shim on drive pinion and press rear
bearing onto pinion. Remove depth gauge from carrier.

NOTE: DO NOT press on roller cage. Press only on bearing inner

race.

IMPULSE DIFFERENTIAL PINION DEPTH SHIMS

Pinion Code Correction Required

+ 6 ............................. Subtract .0024" (.06 mm)

+ 4 ............................. Subtract .0016" (.04 mm)
+ 2 ............................. Subtract .0008" (.02 mm)
0 ............................... No Correction Required
- 2 .................................. Add .0008" (.02 mm)
- 4 .................................. Add .0016" (.04 mm)
- 6 .................................. Add .0024" (.06 mm)




























































FRONT DIFFERENTIAL PINION DEPTH SHIM CHART




























































Dial Indicator reading (Inches)

0.052
Pinion Marking
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ....................................... 1.39(0.0547)
0.053
Pinion Marking
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ....................................... 1.39(0.0547)
-6 ....................................... 1.41(0.0555)
0.054
Pinion Marking
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ....................................... 1.39(0.0547)
-4 ....................................... 1.41(0.0555)
-6 ....................................... 1.43(0.0563)
0.055
Pinion Marking
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
 0 ....................................... 1.39(0.0547)
-2 ....................................... 1.41(0.0555)
-4 ....................................... 1.43(0.0563)
-6 ....................................... 1.45(0.0571)
0.056
Pinion Marking
+6 ................................................ ...
+4 ....................................... 1.39(0.0547)
+2 ....................................... 1.41(0.0555)
0 ....................................... 1.43(0.0563)
-2 ....................................... 1.45(0.0571)
-4 ....................................... 1.47(0.0579)
-6 ....................................... 1.49(0.0587)
0.057
Pinion Marking
+6 ....................................... 1.39(0.0547)
+4 ....................................... 1.41(0.0555)
+2 ....................................... 1.43(0.0563)
0 ....................................... 1.45(0.0571)
-2 ....................................... 1.47(0.0579)
-4 ....................................... 1.49(0.0587)
-6 ....................................... 1.51(0.0594)
0.058
Pinion Marking
+6 ....................................... 1.41(0.0555)
+4 ....................................... 1.43(0.0563)
+2 ....................................... 1.45(0.0571)
0 ....................................... 1.47(0.0579)
-2 ....................................... 1.49(0.0587)
-4 ....................................... 1.51(0.0594)
-6 ....................................... 1.53(0.0602)
0.059
Pinion Marking
+6 ....................................... 1.43(0.0563)
+4 ....................................... 1.45(0.0571)
+2 ....................................... 1.47(0.0579)
0 ....................................... 1.49(0.0587)
-2 ....................................... 1.51(0.0594)
-4 ....................................... 1.53(0.0602)
-6 ....................................... 1.55(0.0610)
0.060
Pinion Marking
+6 ....................................... 1.47(0.0579)
+4 ....................................... 1.49(0.0587)
+2 ....................................... 1.51(0.0594)
0 ....................................... 1.53(0.0602)
-2 ....................................... 1.55(0.0610)
-4 ....................................... 1.57(0.0618)
-6 ....................................... 1.59(0.0626)
0.061
Pinion Marking
+6 ....................................... 1.49(0.0587)
+4 ....................................... 1.51(0.0594)
+2 ....................................... 1.53(0.0602)
0 ....................................... 1.55(0.0610)
-2 ....................................... 1.57(0.0618)
-4 ....................................... 1.59(0.0626)
-6 ....................................... 1.61(0.0634)
0.062
Pinion Marking
+6 ....................................... 1.51(0.0594)
+4 ....................................... 1.53(0.0602)
+2 ....................................... 1.55(0.0610)
 0 ....................................... 1.57(0.0618)
-2 ....................................... 1.59(0.0626)
-4 ....................................... 1.61(0.0634)
-6 ....................................... 1.63(0.0642)
0.063
Pinion Marking
+6 ....................................... 1.55(0.0610)
+4 ....................................... 1.57(0.0618)
+2 ....................................... 1.59(0.0626)
0 ....................................... 1.61(0.0634)
-2 ....................................... 1.63(0.0642)
-4 ....................................... 1.65(0.0650)
-6 ....................................... 1.67(0.0657)
0.064
Pinion Marking
+6 ....................................... 1.57(0.0618)
+4 ....................................... 1.59(0.0626)
+2 ....................................... 1.61(0.0634)
0 ....................................... 1.63(0.0642)
-2 ....................................... 1.65(0.0650)
-4 ....................................... 1.67(0.0657)
-6 ....................................... 1.69(0.0665)
0.065
Pinion Marking
+6 ....................................... 1.59(0.0626)
+4 ....................................... 1.61(0.0634)
+2 ....................................... 1.63(0.0642)
0 ....................................... 1.65(0.0650)
-2 ....................................... 1.67(0.0657)
-4 ....................................... 1.69(0.0665)
-6 ....................................... 1.71(0.0673)
0.066
Pinion Marking
+6 ....................................... 1.61(0.0634)
+4 ....................................... 1.63(0.0642)
+2 ....................................... 1.65(0.0650)
0 ....................................... 1.67(0.0657)
-2 ....................................... 1.69(0.0665)
-4 ....................................... 1.71(0.0673)
-6 ....................................... 1.73(0.0681)
0.067
Pinion Marking
+6 ....................................... 1.65(0.0650)
+4 ....................................... 1.67(0.0657)
+2 ....................................... 1.69(0.0665)
0 ....................................... 1.71(0.0673)
-2 ....................................... 1.73(0.0681)
-4 ....................................... 1.75(0.0689)
-6 ....................................... 1.77(0.0697)
0.068
Pinion Marking
+6 ....................................... 1.67(0.0657)
+4 ....................................... 1.69(0.0665)
+2 ....................................... 1.71(0.0673)
0 ....................................... 1.73(0.0681)
-2 ....................................... 1.75(0.0689)
-4 ....................................... 1.77(0.0697)
-6 ................................................ ...
0.069
Pinion Marking
+6 ....................................... 1.69(0.0665)
+4 ....................................... 1.71(0.0673)
+2 ....................................... 1.73(0.0681)
 0 ....................................... 1.75(0.0689)
-2 ....................................... 1.77(0.0697)
-4 ................................................ ...
-6 ................................................ ...
0.070
Pinion Marking
+6 ....................................... 1.71(0.0673)
+4 ....................................... 1.73(0.0681)
+2 ....................................... 1.75(0.0689)
0 ....................................... 1.77(0.0697)
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...
0.071
Pinion Marking
+6 ....................................... 1.75(0.0689)
+4 ....................................... 1.77(0.0697)
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...
0.072
Pinion Marking
+6 ....................................... 1.77(0.0697)
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...




























































REAR DIFFERENTIAL PINION DEPTH SHIM CHART




























































Dial Indicator reading (Inches)

0.081
Pinion Marking
+10 ................................................ ...
+8 ................................................ ...
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...
-8 ................................................ ...
-10 ....................................... 2.18(0.0858)
0.082
Pinion Marking
+10 ................................................ ...
+8 ................................................ ...
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...
-8 ....................................... 2.18(0.0858)
-10 ....................................... 2.20(0.0866)
0.083
Pinion Marking
+10 ................................................ ...
+8 ................................................ ...
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ....................................... 2.18(0.0858)
-8 ....................................... 2.20(0.0866)
-10 ....................................... 2.24(0.0882)
0.084
Pinion Marking
+10 ................................................ ...
+8 ................................................ ...
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ....................................... 2.18(0.0858)
-6 ....................................... 2.20(0.0866)
-8 ....................................... 2.24(0.0882)
-10 ....................................... 2.26(0.0890)
0.085
Pinion Marking
+10 ................................................ ...
+8 ................................................ ...
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ....................................... 2.18(0.0858)
-4 ....................................... 2.20(0.0866)
-6 ....................................... 2.24(0.0882)
-8 ....................................... 2.26(0.0890)
-10 ....................................... 2.28(0.0898)
0.086
Pinion Marking
+10 ................................................ ...
+8 ................................................ ...
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ....................................... 2.18(0.0858)
-2 ....................................... 2.20(0.0866)
-4 ....................................... 2.24(0.0882)
-6 ....................................... 2.26(0.0890)
-8 ....................................... 2.28(0.0898)
-10 ....................................... 2.32(0.0914)
0.087
Pinion Marking
+10 ................................................ ...
+8 ................................................ ...
+6 ................................................ ...
+4 ................................................ ...
+2 ....................................... 2.18(0.0858)
0 ....................................... 2.20(0.0866)
-2 ....................................... 2.24(0.0882)
-4 ....................................... 2.26(0.0890)
-6 ....................................... 2.28(0.0898)
 -8 ....................................... 2.32(0.0914)
-10 ....................................... 2.34(0.0921)
0.088
Pinion Marking
+10 ................................................ ...
+8 ................................................ ...
+6 ................................................ ...
+4 ....................................... 2.18(0.0858)
+2 ....................................... 2.20(0.0866)
0 ....................................... 2.24(0.0882)
-2 ....................................... 2.26(0.0890)
-4 ....................................... 2.28(0.0898)
-6 ....................................... 2.32(0.0914)
-8 ....................................... 2.34(0.0921)
-10 ....................................... 2.36(0.0929)
0.089
Pinion Marking
+10 ................................................ ...
+8 ................................................ ...
+6 ....................................... 2.18(0.0858)
+4 ....................................... 2.20(0.0866)
+2 ....................................... 2.24(0.0882)
0 ....................................... 2.26(0.0890)
-2 ....................................... 2.28(0.0898)
-4 ....................................... 2.32(0.0914)
-6 ....................................... 2.34(0.0921)
-8 ....................................... 2.36(0.0929)
-10 ....................................... 2.38(0.0937)
0.090
Pinion Marking
+10 ................................................ ...
+8 ....................................... 2.18(0.0858)
+6 ....................................... 2.20(0.0866)
+4 ....................................... 2.24(0.0882)
+2 ....................................... 2.26(0.0890)
0 ....................................... 2.28(0.0898)
-2 ....................................... 2.32(0.0914)
-4 ....................................... 2.34(0.0921)
-6 ....................................... 2.36(0.0929)
-8 ....................................... 2.38(0.0937)
-10 ....................................... 2.42(0.0953)
0.091
Pinion Marking
+10 ....................................... 2.18(0.0858)
+8 ....................................... 2.20(0.0866)
+6 ....................................... 2.24(0.0882)
+4 ....................................... 2.26(0.0890)
+2 ....................................... 2.28(0.0898)
0 ....................................... 2.32(0.0914)
-2 ....................................... 2.34(0.0921)
-4 ....................................... 2.36(0.0929)
-6 ....................................... 2.38(0.0937)
-8 ....................................... 2.42(0.0953)
-10 ....................................... 2.44(0.0961)
0.092
Pinion Marking
+10 ....................................... 2.20(0.0866)
+8 ....................................... 2.24(0.0882)
+6 ....................................... 2.26(0.0890)
+4 ....................................... 2.28(0.0898)
+2 ....................................... 2.32(0.0914)
0 ....................................... 2.34(0.0921)
-2 ....................................... 2.36(0.0929)
 -4 ....................................... 2.38(0.0937)
-6 ....................................... 2.42(0.0953)
-8 ....................................... 2.44(0.0961)
-10 ....................................... 2.46(0.0969)
0.093
Pinion Marking
+10 ....................................... 2.24(0.0882)
+8 ....................................... 2.26(0.0890)
+6 ....................................... 2.28(0.0898)
+4 ....................................... 2.32(0.0914)
+2 ....................................... 2.34(0.0921)
0 ....................................... 2.36(0.0929)
-2 ....................................... 2.38(0.0937)
-4 ....................................... 2.42(0.0953)
-6 ....................................... 2.44(0.0961)
-8 ....................................... 2.46(0.0969)
-10 ....................................... 2.48(0.0977)
0.094
Pinion Marking
+10 ....................................... 2.26(0.0890)
+8 ....................................... 2.28(0.0898)
+6 ....................................... 2.32(0.0914)
+4 ....................................... 2.34(0.0921)
+2 ....................................... 2.36(0.0929)
0 ....................................... 2.38(0.0937)
-2 ....................................... 2.42(0.0953)
-4 ....................................... 2.44(0.0961)
-6 ....................................... 2.46(0.0969)
-8 ....................................... 2.48(0.0977)
-10 ....................................... 2.52(0.0992)
0.095
Pinion Marking
+10 ....................................... 2.28(0.0898)
+8 ....................................... 2.32(0.0914)
+6 ....................................... 2.34(0.0921)
+4 ....................................... 2.36(0.0929)
+2 ....................................... 2.38(0.0937)
0 ....................................... 2.42(0.0953)
-2 ....................................... 2.44(0.0961)
-4 ....................................... 2.46(0.0969)
-6 ....................................... 2.48(0.0977)
-8 ....................................... 2.52(0.0992)
-10 ....................................... 2.54(0.1000)
0.096
Pinion Marking
+10 ....................................... 2.32(0.0914)
+8 ....................................... 2.34(0.0921)
+6 ....................................... 2.36(0.0929)
+4 ....................................... 2.38(0.0937)
+2 ....................................... 2.42(0.0953)
0 ....................................... 2.44(0.0961)
-2 ....................................... 2.46(0.0969)
-4 ....................................... 2.48(0.0977)
-6 ....................................... 2.52(0.0992)
-8 ....................................... 2.54(0.1000)
-10 ....................................... 2.56(0.1008)
0.097
Pinion Marking
+10 ....................................... 2.34(0.0921)
+8 ....................................... 2.36(0.0929)
+6 ....................................... 2.38(0.0937)
+4 ....................................... 2.42(0.0953)
+2 ....................................... 2.44(0.0961)
 0 ....................................... 2.46(0.0969)
-2 ....................................... 2.48(0.0977)
-4 ....................................... 2.52(0.0992)
-6 ....................................... 2.54(0.1000)
-8 ....................................... 2.56(0.1008)
-10 ................................................ ...
0.098
Pinion Marking
+10 ....................................... 2.36(0.0929)
+8 ....................................... 2.38(0.0937)
+6 ....................................... 2.42(0.0953)
+4 ....................................... 2.44(0.0961)
+2 ....................................... 2.46(0.0969)
0 ....................................... 2.48(0.0977)
-2 ....................................... 2.52(0.0992)
-4 ....................................... 2.54(0.1000)
-6 ....................................... 2.56(0.1008)
-8 ................................................ ...
-10 ................................................ ...
0.099
Pinion Marking
+10 ....................................... 2.38(0.0937)
+8 ....................................... 2.42(0.0953)
+6 ....................................... 2.44(0.0961)
+4 ....................................... 2.46(0.0969)
+2 ....................................... 2.48(0.0977)
0 ....................................... 2.52(0.0992)
-2 ....................................... 2.54(0.1000)
-4 ....................................... 2.56(0.1008)
-6 ................................................ ...
-8 ................................................ ...
-10 ................................................ ...
0.100
Pinion Marking
+10 ....................................... 2.42(0.0953)
+8 ....................................... 2.44(0.0961)
+6 ....................................... 2.46(0.0969)
+4 ....................................... 2.48(0.0977)
+2 ....................................... 2.52(0.0992)
0 ....................................... 2.54(0.1000)
-2 ....................................... 2.56(0.1008)
-4 ................................................ ...
-6 ................................................ ...
-8 ................................................ ...
-10 ................................................ ...
0.101
Pinion Marking
+10 ....................................... 2.44(0.0961)
+8 ....................................... 2.46(0.0969)
+6 ....................................... 2.48(0.0977)
+4 ....................................... 2.52(0.0992)
+2 ....................................... 2.54(0.1000)
0 ....................................... 2.56(0.1008)
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...
-8 ................................................ ...
-10 ................................................ ...
0.102
Pinion Marking
+10 ....................................... 2.46(0.0969)
+8 ....................................... 2.48(0.0977)
+6 ....................................... 2.52(0.0992)
 +4 ....................................... 2.54(0.1000)
+2 ....................................... 2.56(0.1008)
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...
-8 ................................................ ...
-10 ................................................ ...
0.103
Pinion Marking
+10 ....................................... 2.48(0.0977)
+8 ....................................... 2.52(0.0992)
+6 ....................................... 2.54(0.1000)
+4 ....................................... 2.56(0.1008)
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...
-8 ................................................ ...
-10 ................................................ ...
0.104
Pinion Marking
+10 ....................................... 2.52(0.0992)
+8 ....................................... 2.54(0.1000)
+6 ....................................... 2.56(0.1008)
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...
-8 ................................................ ...
-10 ................................................ ...
0.105
Pinion Marking
+10 ....................................... 2.54(0.1000)
+8 ....................................... 2.56(0.1008)
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...
-8 ................................................ ...
-10 ................................................ ...
0.106
Pinion Marking
+10 ....................................... 2.56(0.1008)
+8 ................................................ ...
+6 ................................................ ...
+4 ................................................ ...
+2 ................................................ ...
0 ................................................ ...
-2 ................................................ ...
-4 ................................................ ...
-6 ................................................ ...
-8 ................................................ ...
-10 ................................................ ...




























































Pinion Bearing Preload
NOTE: Install new lock nut on pinion.

1) Place drive pinion and new collapsible spacer into

carrier. Lubricate pinion oil seal. Install front pinion bearing and
oil seal. Mount pinion flange on drive pinion, apply lubricant to
pinion threads and install pinion nut.
2) Hold pinion flange and tighten differential nut to
130-202 ft. lbs. (176-274 N.m) on Impulse models, 108-145 ft. lbs.
(146-196 N.m) on Trooper II models and 83-90 (112-122) on P’UP
models. Rotate pinion to ensure bearings are seated.
3) Using torque wrench, note reading required to rotate
flange. Continue tightening nut in small increments until 6-10 INCH
lbs. (.7-1.1 N.m) is required to turn flange.

Fig. 8: Using Torque Wrench to Measure Dr. Pin. Brg Preload

Courtesy of Isuzu Motor Co.

CAUTION: Preload builds quickly. Nut should be tightened only in

small increments and pull scale used after each small amount
of tightening. If preload is exceeded, a new collapsible
spacer must be installed.

Backlash & Side Bearing Preload

1) If original side bearings, differential case, ring and
pinion, and differential carrier are being reused, original shims may
be reinstalled in their respective positions.
2) If only new side bearings are being installed, measure
new bearings with a micrometer and compare thickness with original
bearings. If new bearing is thicker, SUBTRACT difference from shim
pack. If new bearing is thinner, ADD difference to shim pack.
3) If new bearings, and/or differential case, ring and
pinion, or differential carrier are being installed, new shims must
be selected as follows. Install side bearings onto differential case,
but do not install shims at this time.
 4) Mount case into carrier bores. Move ring gear tightly
against carrier on ring gear side (away from pinion), and hold in
this position. Using a feeler gauge, measure clearance between
bearing and differential carrier on side opposite ring gear. Record
clearance.
5) Proper preload is established using predetermined
dimension of .002" (.05 mm). Therefore, ADD this dimension to
clearance obtained in step 3) for proper preload. This will give
required total thickness of both shim packs. Equally divide total
dimension for required shim pack thickness for each side.
6) Remove case from carrier. Remove side bearings and
install shim packs. Reinstall bearings. Install differential case
into carrier, tapping carefully into place.
7) Install side bearing caps in original positions, and
install and tighten attaching bolts. Measure runout of ring gear. If
runout exceeds .002" (.05 mm), correct by cleaning or replacing
parts. See Fig. 9.

Fig. 9: Checking Ring Gear Runout

Courtesy of Isuzu Motor Co.

NOTE: Backlash changes approximately .002" (.05 mm) for each .003"
(.08 mm) shim change.
 8) Mount a dial indicator against ring gear teeth and
measure backlash in 3 locations. Backlash should be .005-.007"
(.13-.18 mm) on rear differential and .004-.006" (.10-.15 mm) on
front differential.
9) If not within specifications, shims behind side bearings
must be adjusted. To increase backlash, right side bearing shim must
be increased and left side bearing decreased. To decrease backlash,
right side bearing shim must be decreased and left side bearing
increased.

NOTE: To maintain preload when backlash is adjusted, total

thickness of both shim packs must not be altered. Therefore,
if it is necessary to increase one shim pack, opposite shim
pack must be decreased by same amount.

AXLE ASSEMBLY SPECS

AXLE ASSEMBLY SPECIFICATIONS TABLE




























































Application In. (mm)

Side & Pinion Gear

Backlash ........................... .001-.003 (.03-.08)
Side Bearing Preload ..................... ( 1) .002 (.05)
Ring Gear Backface Runout ..................... .002 (.05)
Ring Gear Backlash
Front & Rear ....................... .005-.007 (.13-.18)

(1) - Add to side bearing "zero clearance" shim pack.

TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE




























































Application Ft. lbs. (N.m)

Pinion Nut (1)

Impulse .............................. 130-202 (176-274)
P’UP ................................... 83-90 (112-122)
Trooper II ........................... 108-145 (146-196)
Ring Gear Bolt
Impulse ........................................ 62 (85)
P’UP & Trooper II ....................... 72-87 (98-118)
Side Bearing Bolt ......................... 69-76 (93-103)

INCH Lbs. (N.m)

Pinion Bearing Preload (2) ................ 6-10 (.7-1.1)

(1) - Initial setting. Continue tightening until proper

preload is obtained.
(2) - Measured with torque wrench.