Adjusting the position of the drive gear of the gearbox (Chevrolet Tahoe 2)

10.5 inch gearbox

1. Install the gearbox.

Caution: Before servicing the bearing cap, measure and record the thickness of the pinion bearing cap adjusting washer.

2. Install the original pinion bearing cover adjusting washer. If the original washer is not available, install a 0.41mm thick washer.

Caution: Do not apply grease to the washer at this time.

3. Install the bearing cap.

4. Install the bearing cover mounting bolts. Tighten the bolts. Tightening torque 88 N·m.

5. Adjust the engagement clearance.

6. Check the shape and position of the contact patch of the teeth of the drive and driven gears of the gearbox.

7. If the shape and position of the contact patch are not normal, adjust the position of the drive gear:

• a) Loosen the gear bearing cover bolts.
• b) Remove the cover.
• c) Remove the adjusting washer.
• If the contact patch is higher than normal, install a washer one size larger (approximately 0.25 mm).
• If the contact patch is below normal, install a washer one size smaller (approximately 0.25 mm).
• d) Install the selected adjusting washer.
• d) Install the bearing cover.
• e) Install and tighten the bearing cover mounting bolts. Tightening torque 88 N·m.
• g) Check the shape and position of the contact patch of the teeth of the drive and driven gears of the gearbox.

Note: Adjusting washers are available in thicknesses from 0.15 to 0.61 mm with a step of 0.2-0.3 mm.

8. Check the clearance size in the engagement.

8.6" and 9.5" gearboxes

Note: This will require special measuring equipment.

Attention: when taking measurements, all tools, differential side bearing seats and gearbox pinion bearing rings must be absolutely clean.

1. Lubricate the bearings of the drive gear of the reduction gear with transmission oil.

2. Install the pinion bearings into the gearbox housing.

3. Assemble and install the measuring device as shown in the figure.



4. Hold the plug (4) of the device with a torque wrench and turn the nut (3) until a turning torque of 1.7 Nm is obtained. Turn the assembly several times in both directions to seat the bearings.

5. Check the value of the turning torque. If the torque is less than 1.7 Nm, tighten the nut until the torque is in the range of 1.7-2.3 Nm.

6. Install the second device into the gearbox housing as shown in the figure.



7. Install the differential side bearing caps.



8. Install the bearing cap mounting bolts. Tighten the bolts. Tightening torque 75 N·m.

9. Rotate the axle (3) in the disks (1) and (2). The axle should rotate freely in both directions. If there is no free rotation, dismantle the device and inspect all mounting places, eliminate any defects noticed (for example, skew). Reinstall the fixture.



10. Align the plunger of the axle (1) of the device with the measuring platform (2).

11. Install the dial indicator on the device axis as follows:

• a) Loosely slide the indicator mounting clamp onto the axle.
• b) Install the indicator contact pad onto the axle support post.
• c) Create a preliminary indicator stroke of approximately three quarters of a turn of the arrow.
• d) Tighten the indicator clamp.

12. Move the plunger of the axis back and forth and determine the place of greatest deviation of the indicator arrow.

13. At the point of maximum deviation, move the indicator so that the indicator arrow points to zero.

14. Move the plunger of the device axis to confirm that the indicator zero is set correctly.

15. Move the axle plunger away from the measuring platform.





16. The value on the indicator now corresponds to the thickness of the drive gear adjusting washer.

17. Select the appropriate adjusting washer.

18. Remove the measuring devices.

19. Remove the pinion bearings.

20. Install the selected adjusting washer between the gear and the inner bearing.