Rear Axle - 9 1/4

PINION DEPTH-BEARING PRELOAD-GEAR BACKLASH





Ring gear and pinion are supplied as matched sets. Identifying numbers for the ring gear and pinion are painted onto the pinion gear shaft and the side of the ring gear. A plus (+) number, minus (-) number or zero (0) along with the gear set sequence number 01 to 99 is on each gear. This first number (1) is the amount in thousandths of an inch the depth varies from the standard depth setting of a pinion marked with a zero 0. The next two numbers (2) are the sequence number of the gear set. The standard depth provides the best teeth contact pattern.






Compensation for pinion depth variance is achieved with select shims (4) located behind the rear pinion bearing (3).


If installing a new gear, note the depth variance number of the original and replacement pinion. Add or subtract this number from the original depth shim/oil slinger to compensate for the difference in the depth variances. The numbers represent thousands of an inch deviation from the standard. If the number is negative, add that value to the required thickness of the depth shims. If the number is positive, subtract that value from the thickness of the depth shim.


Pinion Gear Depth Variance Chart: Note where Old and New Pinion Marking columns intersect. Intersecting figure represents plus or minus the amount needed.

Pinion Gear Depth Variance:

PINION DEPTH MEASUREMENT






Measurements are taken with pinion bearing cups and pinion bearings installed in the housing. Take measurements with Pinion Gauge Set and Dial Indicator C-3339A (1).





1. Assemble Pinion Height Block 6739 (1) Pinion Block 8542 (1) and rear pinion bearing onto Screw 6741.




2. Insert assembled height gauge components, rear bearing, and screw into the housing through pinion bearing cups.
3. Install front pinion bearing and Cone-Nut 6740 on screw. Tighten cone-nut on screw until Torque To Rotate screw is 1.7 Nm (15 in. Lbs.).
4. Place Arbor Disc 8541 (1) on Arbor D-115-3 (3) in position in the housing side bearing cradles. Install differential bearing caps on arbor discs and tighten cap bolts to 41 Nm (30 ft. lbs.).





NOTE: Arbor Discs 8541 has different step diameters to fit other axles. Choose proper step for axle being serviced.

5. Assemble Dial Indicator C-3339A into Scooter Block D-115-2 and secure set screw.
6. Place Scooter Block/Dial Indicator in axle housing so dial probe and scooter block are flush against the pinion height block. Hold scooter block in place and zero the dial indicator. Tighten dial indicator face lock screw.
7. Slide the dial indicator (3) probe across the gap between the pinion height block and the arbor bar (1) with the scooter block (2) against the pinion height block. Move the dial probe to the crest of the arbor bar and record the highest reading.
8. Select a shim equal to the dial indicator reading plus or minus the pinion depth variance number on the pinion gear. If the depth variance is -2, add 0.002 in. to the dial indicator reading. If the depth variance is +2, subtract 0.002 in. from the dial indicator reading.




9. Install pinion gear and establish Pinion Torque To Rotate (PTTR) with an inch pound torque wrench (1).

DIFFERENTIAL BEARING PRELOAD AND GEAR BACKLASH





1. Turn each thread adjuster inward with Wrench C-4164 until differential bearing end-play is eliminate and ring gear backlash is approximately 0.25 mm (0.01 in.). Seat bearing cups by rapidly rotating the pinion gear a half turn back and forth several times.
2. Install dial indicator (1) with plunger position against drive side of a ring gear tooth. Measure and record backlash at 4 positions, 90 degrees apart around the ring gear.
Mark lowest backlash position on the ring gear and make all backlash measurements at this location.




3. Loosen left-side adjuster and tighten right-side threaded adjuster with Wrench C-4164 (3) to obtain a backlash of 0.076 - 0.102 mm (0.003 - 0.004 in.).
4. Tighten both adjusters to 14 Nm (10 ft. lbs.). Seat differential bearing cups by rapidly rotating the pinion gear a half turn back and forth several times.
5. Tighten differential bearing cap bolts 136 Nm (100 ft. lbs.).
6. Tighten right-side threaded adjuster to 102 Nm (75 ft. lbs.). Seat differential bearing cups by rapidly rotating the pinion gear a half turn back and forth several times. Continue this procedure until right-side adjuster torque remains a constant 102 Nm (75 ft. lbs.).
7. Measure the ring gear backlash. Backlash should be 0.12 - 0.20 mm (0.005 - 0.008 in.).

If backlash is less than 0.12 mm (0.005 in.) increase the right-side threaded adjuster torque until specified backlash is obtained.


If backlash is more than 0.20 mm (0.008 in.) repeat procedure from the beginning.

8. Tighten left-side threaded adjuster to 102 Nm (75 ft. lbs.). Seat differential bearing cups by rapidly rotating the pinion gear a half turn back and forth several times. Continue this procedure until left-side adjuster torque remains a constant 102 Nm (75 ft. lbs.).
9. Install threaded adjuster locks and tighten the lock screws to 10 Nm (90 in. lbs.).
10. Measure and backlash at 4 positions, 90 degrees apart around the ring gear. Maximum ring gear backlash variation is 0.076 mm (0.003 in.).

GEAR CONTACT PATTERN


Gear tooth contact pattern is used to verify the correct running position of the ring and pinion gears. This will produce low noise and long gear life. Gears which are not positioned properly may be noisy and have shorten gear life.

1. Wipe clean each tooth of the ring gear.
2. Apply gear marking compound to all of the ring gear teeth.
3. Verify bearing cap bolts are torque specification.
4. Apply parking brakes lightly to create at 14 Nm (10 ft. lbs.) pinion rotating torque.
5. Rotate the pinion/pinion yoke 4 full revolutions in each directions.
6. Read gear tooth contact pattern.




Gear contact pattern is correct. Backlash and pinion depth is correct.




Ring gear is too far away from the pinion gear, coast side toe (1) drive side heel (2). Decrease the backlash, by moving the ring closer to the pinion gear using the adjusters.




Ring gear is too close to the pinion gear, drive side toe (1) and coast side heel (2). Increase the backlash, by moving the ring away from the pinion gear using the adjusters.




Ring gear is too far away from the pinion gear, drive side heel (1) and coast side heel (2). Decrease the backlash, by moving the ring closer to the pinion gear using the adjusters.




Ring gear is too close to the pinion gear, drive side toe (1) and coast side toe (2). Increase the backlash, by moving the ring away from the pinion gear using the adjusters.




Pinion gear is set too low. Increase the pinion gear height, by increasing the pinion depth shim thickness.




Pinion gear is set too high. Decrease the pinion depth, by decreasing the pinion depth shim thickness.

AXLE SHAFT END-PLAY


Visual inspect differential case, pinion mate shaft, axle shaft end button, C-lock, differential pinion gears, differential side gears and washers for damage or excessive wear. Replace damaged components.

1. Assemble differential and install.
2. Install differential pinion mate shaft locking screw to locate the shaft without torque it down.
3. Mount dial indicator base on the axle tube flange.
4. Push axle shaft inward until its end touches differential pinion mate shaft. Set dial indicator plunger on the end of axle shaft flange surface and zero dial indicator.
5. Pull axle shaft out until it stops and record dial indicator end-play reading. Rotate axle shaft about 180 degrees and record dial indicator end-play reading again. Two readings should be within 0.05 mm (0.002 in.).
6. Conduct the same procedure on the axle shaft on the opposite side.

End-play specification should be 0.13 mm - 0.38 mm (0.005 - 0.015 in.). If specification can not be met, shim side gears and/or replace differential case.