Backlash Adjustment; Gear Tooth Pattern Check - Isuzu 1999 RODEO Workshop Manual

Backlash Adjustment

1. Install the differential case assembly and bearing
caps.
2. Rotate the case several times to seat the bearings.
3. Remove the spreader.
4. Install the side bearing cap bolts.
Tighten side bearing cap bolts
Torque: 108 N·m (80 lb ft)
5. Install a dial indicator to the case using a magnetic
base.
6. Place the indicator stem at the heel end of a tooth.
f Set the dial indicator so that the stem is in line with
the gear rotation and perpendicular to the tooth
angle.
7. Check and record the backlash at three points around
the ring gear.
f The pinion must be held stationary when checking
backlash.
f The backlash should be the same at each point
within 0.07 mm (0.003 in). If the backlash varies
more than 0.07 mm (0.003 in), check for burrs, a
distorted case flange, or uneven bolting conditions.
8. Backlash at the minimum lash point measured should
be between 0.13 and 0.20 mm (0.005 and 0.008 in)
for all new gear sets.
9. If the backlash is not within specifications, move the
ring gear in or out from the pinion by increasing the
thickness of one shims, and decreasing the thickness
of the other shim by the same amount.
This will maintain the correct rear axls side bearing
preload.
f Moving 0.05 mm (0.002 in) worth of shim from one
side of the differential to the other will change the
backlash adjustment by 0.03 mm (0.001 in).
10. After obtaining correct tooth contact described in
later, install ABS speed sensor.
11. Install the cover with sealant.
Torque: 40 N·m (30 lb ft)
12. Fill the axle lubricant.

Gear Tooth Pattern Check

Checking the ring gear to pinion tooth pattern is to be
done only after setting up the axle according to the
methods in this section. The pattern check is NEVER to
be used as an initial check, or instead of checking pinion
depth and backlash adjustments.
This check is only to be verify the correct adjustment of
the gear set after set up.
Legend
(1) Heel
(2) Toe
425RS087
(3) Concave Side (Coast)
(4) Convex Side (Drive)
1. Wipe all oil out of the carrier, and carefully clean each
tooth of the ring gear.
2. Use gear marking compound 1052351 or equivalent
and apply this mixture sparingly to all ring gear teeth,
using a medium-stiff brush. When properly used, the
area of pinion tooth contact will be visible when hand
load is applied.
3. Tighten the bearing cap bolts to the specified torque.
4. Expand the brake shoes until a torque of 54 to 68 N·m
(40 to 50 lb ft.) is required to turn the pinion. A test
made without loading the gears will not give a
satisfactory pattern. Turn the pinion flange with a
wrench so that the ring gear rotates one full
revolution, then reverse the rotation so that the ring
gear rotates one revolution in the opposite direction.
5. Observe the pattern on the ring gear teeth and
compare this with figure.
DIFFERENTIAL (REAR) 4A2–23
425RS038