Tools Required

J 34925  Pinion Setting Gauge and Components

Important:  Make sure all of the tools, the differential side bearing bores, and the pinion bearing cups are clean before proceeding.

1. Lubricate the pinion bearings with axle lubricant. Refer to SPECIFICATIONS in General Information.
2. Install the pinion bearings into the axle housing.
3. Assemble the J 21777-40  (1), the J 21777-43  (2), the J 21777-42  (3), and the J 23597-11  (4) as shown.
   Fig 1: Assembling J 21777-40, J 21777-43, J 21777-42 & J 23597-11

   Courtesy of GENERAL MOTORS CORP.
   NOTE: Refer to FASTENER NOTICE in Cautions and Notices.
4. While holding the J 21777-43  stationary, install and inch-pound torque wrench on the nut of the J 21777-43. 

   Tighten 

   Tighten the nut on the J 21777-43  until a rotating torque of 2.3 N.m (20 lb in) is obtained.

   Rotate the assembly several times in both directions in order to seat the pinion bearings.

5. Check the rotating torque of the assembly. If the rotating torque is less than 1.7 N.m (15 lb in), continue to tighten the nut on the J 21777-43  until a rotating torque of 1.7-2.8 N.m (15-25 lb in) is obtained.
6. Assemble the J 21777-45  (1, 2) to the J 23597-1  (3) and install into the differential carrier bore of the axle housing as shown.
   Fig 2: Assembling J 21777-45 To 23591 & Install Into Differential Carrier Bore Of Axle Housing

   Courtesy of GENERAL MOTORS CORP.
7. Install the bearing caps.
8. Install the bearing cap bolts.

   Tighten 

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

9. Rotate the J 23597-1  within the J 21777-45.  The J 23597-1  must rotate back and forth freely within the discs. If the J 23597-1  does not rotate freely, disassemble the components, inspect for proper seating and/or mis-aligned components and re-assemble.
10. Align the plunger of the J 23597-1  (1) to the J 23597-11  (2).
    Fig 3: Aligning Plunger Of 23597-1 To J 23597-11

    Courtesy of GENERAL MOTORS CORP.
11. Install the J 8001-3  to the J 23597-1  as follows:
    1. 11.1. Loosely clamp the J 8001-3  onto the stem on the J 23597-1. 
    2. 11.2. Place the contact pad of the J 8001-3  onto the mounting post of the J 23597-1. 
    3. 11.3. With the contact pad of the J 8001-3  touching the mounting post of the J 8001-3  touching the mounting post of the J 23597-1,  loosen the lock nut on the J 80013  and push down on the J 8001-3  until the needle the J 8001-3  has turned 3/4 of a turn clockwise.
    4. 11.4. Tighten the clamp on the J 8001-3  finger tight.
12. Move the plunger of the J 23597-1  back and forth until the needle of the J 8001-3  indicates the greatest direction.

    The deflection is the point where the needle Cannes direction.

13. At the greatest point of deflection, move the housing of the J 8001-3  until the needle indicates zero.
    Fig 4: Measuring Pinion Depth

    Courtesy of GENERAL MOTORS CORP.
14. Move the plunger of the J 23597-1  back and forth again to verify the zero setting. Adjust the housing of the J 8001-3  as necessary to set the needle to zero.
15. Rotate the plunger of the J 23597-1  from the J 23597-11  until it no longer touches the J 23597-11. 
16. The value indicated on the J 8001-3  is the thickness of the shim needed in order to set the depth of the pinion.
17. Select the shim that indicates the proper thickness. Measure the shim with a micrometer in order to verify that the thickness is correct.
18. Remove the pinion depth setting tools.
19. Remove the pinion bearings.
20. Install the pinion shim between the pinion gear and the inner pinion bearing. Refer to DRIVE PINION BEARINGS REPLACEMENT .