Drive Pinion Gear Installation & Depth Adjustment
Fig. 13 Pinion variance chart:
Pinion gear depth is the distance, measured in inches, from the end face of the pinion gear to the axle shaft center line. This dimension is controlled by shims installed between the pinion rear bearing and housing assembly. If the pinion is marked +2, the gear set varied from the standard size by +.002 inch and will require 0.002 inch less shims than a set marked zero. When a set is marked + (plus), the distance from the pinion button face to the axle shaft center line must be more than the standard setting. If the pinion is marked - 3, the set varied from standard by - 0.003 inch and will require 0.003 more shims than a set marked zero. When a set is marked zero, the distance from the pinion button face to the axle shaft center line must be less than the standard setting.
1. Measure thickness of pinion depth shim removed during disassembly.
2. Note pinion depth variance numbers on old and new pinion gears.
3. Refer to pinion variance chart and determine amount to be added to or subtracted from original shim to arrive at starter shim thickness. Do not use or assume that the starter shim thickness will be the final shim setting. An actual pinion depth measurement must be performed and the final shim thickness adjusted as necessary.
4. Install pinion front bearing cup into housing bore using tools J-7079-02 and J-25101 or equivalents.
5. Install starter shim into rear bearing bore of housing. Ensure shim is centered in cup bore. If shim is chamfered, chamfer must face toward housing bore, not toward the pinion head.
6. Install pinion rear bearing cup into housing bore. On model 30 axles, install cup using tool J-7079-02 and J-25101 or equivalents. On model 44 and 60 axles, install cup using tools J-25122 and J-25157 or equivalents.
7. On front axle differentials, install oil slinger onto pinion gear. Ensure slinger is seated on pinion head before installing rear bearing.
8. Install rear bearing onto pinion. On model 30 axles, install cup using tool J-5590 or equivalent. On model 44 and 60 axles, install bearing using tool J-24433 or equivalent.
9. Install pinion gear into axle housing.
10. Install pinion front bearing, pinion yoke, washer and original pinion nut onto pinion. Tighten nut only enough to remove end play and provide 10-15 inch lbs. of drag torque when pinion is rotated. Do not install pinion seal, slinger or dust cap at this time. The pinion will be removed after measurement and adjustment of pinion depth.
11. Note pinion depth variance marked on pinion gear. If number is preceded by a plus (+) sign, add that amount (in thousands) to standard setting. If number is preceded by a minus ( - ) sign, subtract that amount (in thousands) from standard setting. Result of addition or subtraction is desired pinion depth. Record reading. If the gear is marked zero (0), use the standard setting.
12. Assemble gauge arbor tool J-5223-4 and discs. On model 30 axles, use discs J-5223-26 or equivalent. On model 44 and 60 axles, use discs tool J-5223-25 or equivalent.
13. Install assembled arbor and discs into differential, tighten bearing cap bolts securely. Ensure discs are firmly seated in bearing cup bores.
14. Remove standard plunger from gauge block tool J-5223-20 and install plunger tool J-5223-27. Compress plunger completely and tighten gauge block screw securely.
15. Install gauge block tool J-4223-20 or equivalent. Position block so plunger is directly under arbor J-5223-4, and flat surface on anvil side of block is seated on end face of pinion. To avoid false readings, do not allow the anvil to contact the pinion gear at any point.
16. Assemble bolt J-5223-29 and clamp J-5223-24 and mount tool on to axle housing.
17. Extend clamp bolt until it presses against gauge block. Align gauge block plunger with center of gauge arbor and tighten clamp bolt until it presses against block with enough force to prevent block from moving.
18. Loosen gauge block screw and release plunger. When plunger contacts arbor tool, tighten screw to lock plunger in position.
19. Remove clamp and bolt from axle housing.
20. Remove gauge block and measure distance from end of anvil to end of plunger. This measurement represents measured pinion depth. Record this reading for assembly reference.
21. If measured pinion depth equals the desired pinion depth, the installed shim thickness is correct and further adjustment is not required.
22. Remove bearing caps, arbor tool and discs.
23. Remove pinion gear, rear bearing cup and depth shim from axle housing.
24. Measure thickness of depth shim just removed from housing and add this dimension to measured pinion depth obtained in previous step. From this total, subtract desired pinion depth. Result represents shim thickness required to adjust pinion depth. The desired pinion depth is the standard setting plus or minus the pinion depth variance.