The 9.25 is one of the ezest rear diff's to work on made just shy of the F 9".
Differential Case Installation
1.Apply a coating of hypoid gear lubricant to the differential bearings, bearing cups and the threaded adjusters. Carefully position the assembled differential case in the housing.
2 Observe the reference marks and install the differential bearing caps at their original locations
3 Install the bearing cap bolts. Tighten the upper bolts to 10 ft. lbs. (14 Nm). Tighten the lower bolts finger-tight until the bolt head is lightly seated.
Bearing Preload Torque and Ring Gear Backlash Adjustment
The following limitations must be considered when adjusting the differential bearing preload torque and ring gear backlash. The maximum permissible ring gear backlash variation is 0.003 in. (0.076mm). For example, if the minimum backlash is 0.006 in. (0.152mm) at one location, the maximum can be no more than 0.009 in. (0.229mm) at another location.
This variation represents the maximum permissible run-out and it is important to mark the gears so the same teeth are engaged (meshed) during all backlash measurements. It is also important to maintain the specified threaded-adjuster torque while adjusting the differential bearing preload torque and the ring gear backlash. Excessive adjuster torque will introduce a high bearing load and cause premature bearing failure. Insufficient adjuster torque can result in excessive differential case free-play and ring gear noise.
The differential bearing cups will not always immediately follow the threaded adjusters as they are moved during adjustment. Ensure accurate bearing cup responses to the adjustments. Maintain the gear teeth engaged (meshed) as marked. The bearings must be seated by rapidly rotating the pinion gear a half turn back and forth. Do this five to ten times each time the threaded adjusters are adjusted.
1. Use Wrench C-4164, or equivalent, to adjust each threaded adjuster inward until the differential bearing free-play is eliminated. Allow some ring gear backlash (approximately 0.01 in. or 0.25mm) between the ring and pinion gear. Seat the bearing cups with the procedure described previously.
2. Install Dial Indicator C-3339, or equivalent. Position the plunger against the drive side of a ring gear tooth. Measure the backlash at 4 positions around the perimeter of the ring gear (with an arc interval of approximately 90° between each position) to locate the area of minimum backlash.
3. Rotate the ring gear to the position of the least backlash (as indicated by the dial indicator pointer). Mark the gear so that all future backlash measurements will be taken with the same gear teeth meshed.
4. Loosen the right-side, tighten the left-side threaded adjuster. Obtain backlash of 0.003-0.004 (0.076-0.102mm) with each adjuster tightened to 10 ft. lbs. (14 Nm). Seat the bearing cups with the procedure described previously.
5 Tighten the differential bearing cap bolts. On 83/8 in. diameter to 70 ft. lbs. (95 Nm). On 91/4 in. diameter with 100 ft. lbs. (136 Nm).
6. Use Wrench C-4164, or equivalent, to tighten the right-side threaded adjuster to 75 ft. lbs. (102 Nm). Seat the bearing rollers as previously described. Continue to tighten the right-side adjuster and seat bearing rollers until the torque remains constant at 75 ft. lbs. (102 Nm).
7. Measure the ring gear backlash. If the backlash is not 0.006-0.008 in. (0.15-0.20 mm), continue increasing the torque at the right-side adjuster until obtained. Continue increasing the torque at the right-side threaded adjuster (seat the bearing cups with the procedure described above) until the specified backlash is obtained.
If all the instructions have been correctly completed, the left-side threaded adjuster should be approximately 75 ft. lbs. (102 Nm). If the torque is substantially less, the complete procedure must be completed.
1. Tighten the left-side threaded adjuster until 75 ft. lbs. (102 Nm) is indicated. Seat the bearing rollers with the procedure previously described. Do this until the torque remains constant.
2. After the adjustments are completed, install the threaded adjuster locks. On 91/4 in. diameter, the lock teeth are engaged with the the adjuster threads. On 83/8 in. diameter, the lock finger is engaged with an adjuster hole. Tighten the lock screws to 90 inch lbs. (10 Nm).