Backlash Inspection and Adjustment

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Tools Required

J 8001 Dial Indicator Set. See Special Tools and Equipment .
J 36599-A Side Bearing Nut Wrench. See Special Tools and Equipment .
J 36615 Side Bearing Nut Wrench. See Special Tools and Equipment .

Mark the location of the differential adjuster nut sleeves in relation to the differential carrier halves.
Ensure that the notches can be counted when turned.
Install the J 8001-1 (1, 2), the J 8001-2 (3), and the J 8001-3 (4) as shown.
Ensure that the button contacts the outer edge of the pinion yoke and that the plunger is at a right angle to the pinion yoke.

Fig 1: Installing J 8001-1, J 8001-2 & J 8001-3 To Pinion Yoke

Courtesy of GENERAL MOTORS CORP.

Move the pinion yoke back and forth through the pinion yoke's free play while not allowing the ring gear to move.
Record the dial indicator reading.
To determine the actual backlash, divide the dial indicator reading by 2.
An actual dial indicator reading of 0.16 mm (0.006 in) means that there is actually 0.08 mm (0.003 in) backlash.

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 specification of 0.13-0.18 mm (0.005-0.007 in).

IMPORTANT: When adjusting the backlash, observe the following:

Always turn the left and the right differential adjuster nut sleeves in equal amounts.
Turning the differential adjuster nut sleeves one notch will change the backlash about 0.08 mm (0.003 in).

If the backlash is too small, increase the backlash by turning the left differential adjuster nut sleeve in one notch using the J 36599-A , 8.25 inch axle, or the J 36615 , 9.25 inch axle, and the right differential adjuster nut sleeve out one notch using the J 36599-A .
If the backlash is too large, decrease the backlash by turning the right differential adjuster nut sleeve in one notch using the J 36599-A and the left differential adjuster nut sleeve out one notch using the J 36599-A , 8.25 inch axle, or the J 36615 , 9.25 inch axle.
Recheck the backlash and adjust as necessary.
Recheck the rotating torque of the pinion and differential assembly and adjust as necessary.
Once the backlash and rotating torque of the pinion and differential assembly is correct, perform a gear tooth contact pattern check to ensure proper contact between the pinion and the ring gear. Refer to Gear Tooth Contact Pattern Inspection .