Differential Assembly: Adjustments

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 (2) (01 to 99) is on each gear. This first number (1) the amount (in thousandths of an inch) the depth varies from the standard depth setting of a pinion marked with a (0). The next two numbers 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). The shims are placed behind the rear pinion bearing.

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 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 6730 and Dial Indicator C-3339A (1).





1. Assemble Pinion Height Block 6739 (2), Pinion Block 8540 (1) and rear pinion bearing onto Screw 6741.
2. Insert assembled height gauge components, rear bearing and screw into housing through pinion bearing cups.





3. Install front pinion bearing and Cone-Nut 6740 on the screw. Tighten Cone-Nut until Torque To Rotate screw is 1.7 Nm (15 in. lbs.).
4. Place Arbor Disc 8541A (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.).





5. Assemble Dial Indicator C-3339A (3) into Scooter Block D-115-2A (2) and secure set screw.
6. Place Scooter Block/Dial Indicator in position in axle housing so dial probe and scooter block are flush against the rearward surface of the pinion height block. Hold scooter block in place and zero the dial indicator. Tighten dial indicator face lock screw.
7. Slowly slide the dial indicator probe over the edge of the pinion height block.
8. Slide the dial indicator probe across the gap between the pinion height block and the arbor bar (1) with the scooter block against the pinion height block. When dial probe contacts the arbor bar, the dial pointer will turn clockwise. Continue moving the dial probe to the crest of the arbor bar and record the highest reading. If the dial indicator can not achieve a zero reading, the rear bearing cup or the pinion depth gauge set is not installed correctly.
9. Select a shim equal to the dial indicator reading, plus the drive pinion gear depth variance number marked on the shaft of the pinion. If the depth variance is -2, add 0.002 in. to the dial indicator reading. If the depth variance is -2, add 0.002 in. subtract dial indicator reading. Then subtract 0.041 mm (0.0016 in.) from the total measurement. This will be the correct pinion height shim selection.





10. 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 C-3339A (1) with plunger position against drive side of a ring gear (2) 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 95 Nm (70 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 (0.005 in.) increase right-side threaded adjuster torque until specified backlash is obtained.

If backlash is more than 0.20 (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.).

After backlash is achieved, perform Gear Contact procedure.

GEAR CONTACT PATTERN





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 specifications.
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 backlash by moving ring closer to the pinion gear using the adjusters.




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




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




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




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




Pinion gear is set too high. Decrease pinion height 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 specifications should be 0.13 - 0.38 mm (0.005 - 0.015 in.). If specifications can not be met, shim side gears and/or replace differential case.