Hummer H3. Manual — part 1017

11. Remove the BENT shim from the right side of the axle housing.

12. Insert one 4.318 mm (0.170 in) thick service spacer into the right side axle housing.

13. Move the differential assembly towards the left side of the axle housing. While holding the

differential assembly against the left side shim pack, insert progressively larger service shims
between the service spacer and the differential side bearing cup until a moderate resistance
can be felt.

14. Once the largest service shim has been determined, measure the thickness of the shim using a

micrometer. Verify the thickness of the service shim. Measure the service shim in 3
locations. Calculate the average of the 3 measurements. Use the average as the thickness for
the shim. Record the measurement.

15. In order to preload the differential side bearing and set the initial backlash to approximately

0.127 mm (0.005 in), adjust the thickness of left and right side shims by doing the following:

1. Subtract 0.152 mm (0.006 in) from the measurement recorded for the left side shim in

step 9. Record the measurement.

2. Add 0.356 mm (0.014 in) to the measurement recorded for the right side shim in step

14.

16. Select the correct service shim thickness for each side corresponding to the measurements

determined above. Using a micrometer, verify the thickness of the service shim. Measure the
service shim in 3 locations. Calculate the average of the 3 measurements. Use the average as
the thickness for the shim.

17. Install the left side service shim into the axle housing. The service shim must be installed

between the service spacer and the differential side bearing cup.

18. Move the differential assembly towards the left side of the axle housing.

19. Install the right side service shim into the axle housing using the J 25588 , if necessary. The

service shim must be installed between the service spacer and the differential side bearing
cup.

20. Install the differential bearing caps and bolts.

Tighten: Tighten the differential bearing cap bolts to 75 N.m (55 lb ft).

21. Rotate the pinion several times to ensure the bearings have seated.

22. Measure the rotating torque of drive pinion and differential case side bearings using an inch-

pound torque wrench.

Specification: The rotating torque of the drive pinion and differential side bearings should
be 3.9-6.2 N.m (30-55 lb in) for new bearings or 2.8-5.6 N.m (25-50 lb in) for used
bearings.

2007 Hummer H3

2007 Driveline/Axle Rear Drive Axle - H3

Record the measurement.

23. Determine the preload for the differential side bearings by performing the following

calculation:

1. Subtract the drive pinion rotating torque, measured in step 2, from the drive pinion and

differential case side bearing rotating torque, measured in step 22.

2. Multiply the value obtained by the axle ratio. This value equals the preload for the

differential side bearings.

Specification: The differential side bearing preload should be 1.7-4.0 N.m (15-35 lb
in).

24. If the differential side bearing preload is not within specifications, add or subtract shim

thickness equally from each shim pack as necessary in order to increase/decrease the side
bearing preload.

25. Once the differential side bearing preload is within specifications, measure the backlash

between the ring gear and the drive pinion and adjust, if necessary. Refer to Backlash
Adjustment.

26. Once backlash and differential side bearing preload is within specifications, perform a gear

tooth contact pattern check in order to ensure proper alignment between the ring and pinion
gears. Refer to Gear Tooth Contact Pattern Inspection.

BACKLASH ADJUSTMENT

Tools Required

J 8001 Dial Indicator Set

J 25025 Guide Pins

J 25588 Side Bearing Shim Installer

Adjustment Procedure

2007 Hummer H3

2007 Driveline/Axle Rear Drive Axle - H3

Fig. 121: Measuring Ring Gear Backlash
Courtesy of GENERAL MOTORS CORP.

1. Install the J 25025-1 and the J 8001 to the axle housing as shown. See Special Tools.

2. Place the indicator stem of the J 8001 at the heel end of a gear tooth.

3. Set the J 8001 so that the stem is aligned with the gear rotation and perpendicular to the

tooth angle.

4. Preload the dial of the J 8001 .

Align the needle and the dial face of the J 8001 to ZERO.

5. While holding the drive pinion stationary, move the ring gear back and forth.

Measure and record the backlash.

6. Repeat the measuring procedure at eight points around the ring gear.

2007 Hummer H3

2007 Driveline/Axle Rear Drive Axle - H3

Specification: The difference between the backlash at all of the measuring points should
not vary by more than 0.05 mm (0.002 in).

7. If the difference between the backlash at all of the measuring points varies by more than

0.05 mm (0.002 in), inspect for the following conditions:

Burrs

A distorted case flange

Uneven bolting

8. If the difference between all the measuring points is within specifications, the backlash at

the minimum lash point measured should be:

Specification: The backlash between the ring gear and the drive pinion should be between
0.08-0.25 mm (0.003-0.010 in) with a preferred backlash of 0.13-0.18 mm (0.005-0.007
in).

9. If the backlash is too small, increase the backlash using the following procedure:

1. Remove the bearing cap bolts and the bearing caps.

Mark the bearing caps left or right.

2. Remove the differential case assembly with the bearing cups and the shims.

Mark the bearing cups and the shims left or right.

3. Measure the thickness of left side shim pack.

Measure the production shim or the shim and service spacer in 3 locations.

Measure each shim separately.

IMPORTANT:

Do not use the original cast iron production shims to
adjust the backlash. Use service shims and spacers
instead.

Adjust the thickness of the shim pack on each side of
the differential in equal amounts. This will maintain the
correct axle side bearing preload.

Moving 0.05 mm (0.002 in) of shim thickness from one
side of the differential to the other will change the
backlash adjustment approximately 0.03 mm (0.001 in).

2007 Hummer H3

2007 Driveline/Axle Rear Drive Axle - H3