Differential Assembly: Adjustments

PINION DEPTH-BEARING RELOAD-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/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 (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 3.4 Nm (30 in. lbs.).
4. Place Arbor Disc 8541A (1) on Arbor D-115-3 (3) and 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-115-2 (2) and secure set screw.
6. Place Scooter Block with Dial Indicator on the pinion height block, so dial probe and scooter block is 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 probe over the edge of the pinion height block and on to the arbor bar (1). With the scooter block against the pinion height block.
8. When dial probe contacts the arbor bar, the dial pointer will turn clockwise. Continue moving the dial indicator to the crest of the arbor bar and record the highest reading.
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. For example, if the depth variance is -2, add +0.002 in. to the dial indicator reading. Then subtract 0.04064 mm (0.0016 in.) from the total measurement. This will be the correct shim selection for the pinion height.

DIFFERENTIAL BEARING PRELOAD AND GEAR BACKLASH





1. Turn each thread adjuster inward with Wrench C-4164 until differential bearing end-play is eliminated and ring gear backlash approximately 0.25 mm (0.01 in.). Seat differential bearing cups by rapidly rotating the pinion gear a half a turn back and forth several times.
2. Install dial indicator (1) with plunger position against drive side of the ring gear (2). 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 adjuster with Adjuster Wrench C-4164 (3) to obtain backlash of 0.076 - 0.102 mm (0.003 - 0.004 in.).
4. Tighten both adjuster tightened to 14 Nm (10 ft. lbs.). Seat differential bearing cups by rapidly rotating the pinion gear a half a turn back and forth several times.
5. Tighten differential bearing cap bolts to 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 a turn back and forth several times. Continue to tighten the right-side adjuster and seat bearing cups until the torque remains constant at 102 Nm (75 ft. lbs.).
7. Measure the ring gear backlash. The range of backlash is 0.12 - 0.20 mm (0.005 - 0.008 in.).
If backlash is less than 0.12 - 0.20 mm (0.005 - 0.008 in.) increase right-side threaded adjuster torque until specified backlash is obtained. If backlash is more than 0.12 - 0.20 mm (0.005 - 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 a turn back and forth several times. Continue this procedure until left-side adjuster torque remains constant at 102 Nm (75 ft. lbs.).
9. Install the threaded adjuster locks and tighten the lock screws to 11 Nm (8 ft. lbs.).
10. Measure backlash at 4 positions 90 degrees apart around the ring gear. Maximum ring gear backlash variation is 0.076 mm (0.003 in.).

After the proper backlash is achieved, perform the 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 to 136 Nm (100 ft. lbs.).
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.