Differential Assembly: Adjustments

ADJUSTMENTS

Special Tools:


















Ring gear and pinion are supplied as matched sets. Identifying numbers for the ring gear and pinion are laser etched onto the pinion gear shaft and the side of the ring gear. The first number (1) is the gear set sequence number and will be the same for the pinion and ring gear. The second line (2) has a plus (+) followed by a variance number. The third line (3) is the last six digits of the part number.





Compensation for pinion gear (5) depth variance is achieved with select shims (3). The shims are placed behind the rear pinion bearing cup (6).

Calculating the pinion depth variance will require some simple math. If the number etched in the pinion is greater than the standard pinion depth of 117.475 in millimeters, Subtract the standard pinion depth (117.475) from the number etched in the pinion. This will indicate a positive (+) number and will be subtracted from the calculated shim thickness later in the procedure. If the number etched in the pinion is less than the standard pinion depth (117.475), Subtract the number etched in the pinion from the standard pinion depth (117.475). This will indicate a negative (-) number and will be added to the calculated shim thickness later in the procedure. Record the calculated pinion depth variance, positive (+) or negative (-), for later use.

Example: New pinion has a marking of 117.485. Subtract 117.475 from 117.485 (117.485 - 117.475 = positive (+) 0.010 because the markings on the pinion were greater than the standard of 117.475). New Pinion has a marking of 117.465. Subtract 117.465 from 117.475 (117.475 - 117.465 = negative (-) 0.010 because the markings on the pinion were less than the standard of 117.475).

PINION DEPTH MEASUREMENT





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

1. Assemble (6739) (3), (8542) (6) and rear pinion bearing onto (6741) (5).





2. Insert pinion block (1), pinion height block (2), rear bearing, and screw into the housing through pinion bearing cups.
3. Install front pinion bearing and (6740) onto the screw. Tighten cone-nut until Torque To Rotate of the screw is 2.5 Nm (22 in. lbs.).





4. Place (8541A) (1) on (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 (C-3339A) (3) into (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. 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. Continue moving the dial probe to the crest of the arbor bar and record the highest reading.

NOTE: Subtracting 0.035 mm (0.001) from the over all calculation is to compensate for the bearing growth factor.

8. Select a shim equal to the dial indicator reading plus or minus the pinion depth variance calculated earlier, then subtract 0.035 mm (0.001 in.) from the over all calculations. If the calculated pinion depth variance recorded earlier is positive (+), subtract the calculated number from the dial indicator reading. If the calculated pinion depth variance recorded earlier is negative (-), add the calculated number to the dial indicator reading.
9. Remove pinion head bearing cup from case and re-install with selected shim behind the bearing cup.





10. Install a new collapsible spacer (1) on the pinion shaft.
11. Lubricate rear pinion bearing and install pinion gear into the housing.
12. Install companion flange with (C-3718) and (6719A).





13. Install bolts into two of the threaded holes in the companion flange 180° apart.
14. Position (6719A) (2) against the companion flange and install a bolt and washer into one of the remaining threaded holes. Tighten the bolts so the (6719A) is held to the flange.
15. Install pinion washer and a new pinion nut. The convex side of the washer must face outward.
16. Hold companion flange with (6719A) (2) and tighten pinion nut with a torque wrench (3) to 285 Nm (210 ft. lbs.). NOTE: Do not exceed minimum torque 285 Nm (210 ft. lbs.) at this point.






17. Rotate pinion several times to seat pinion bearings.
18. Measure pinion torque to rotate (1) with an inch pound torque wrench (2). Measure pinion rotating torque frequently to avoid over-crushing the collapsible spacer.Pinion Torque To Rotate is:

- Original Bearings: 1 - 2.25 Nm (10 - 20 in. lbs.)
- New Bearings: 1.9 - 2.5 Nm (17 - 22 in. lbs.)
NOTE: If pinion torque to rotate is low, tighten pinion nut in 6.8 Nm (5 ft. lbs.) increments until pinion torque to rotate is achieved.

CAUTION: Never loosen pinion nut to decrease pinion bearing rotating torque. If pinion torque to rotating is exceeded a new collapsible spacer must be installed. Failure to follow these instruction will damage the axle.


DIFFERENTIAL BEARING PRELOAD AND GEAR BACKLASH





1. Before installing differential, use a 12 inch caliper to measure between the inner most part of the holes (1 and 2) and record reading for later use.
2. Install the differential and bearing caps and tighten to 14 Nm (10 ft. lbs.) to retain cups while adjusting.





3. Turn left-side thread adjuster inward with (C-4164) until differential bearing end-play is eliminate and ring gear backlash is approximately 0.025 mm (0.001 in.). Turn right-side thread adjust until it stops. Seat bearing cups by rapidly rotating the pinion gear a half turn back and forth several times.
4. 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.





5. Loosen left-side adjuster and tighten right-side threaded adjuster with (C-4164) (3) to obtain a backlash of 0.076 - 0.102 mm (0.003 - 0.004 in.).
6. 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.
7. Tighten differential bearing cap bolts 136 Nm (100 ft. lbs.).
8. 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.).
9. 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 torque on the right-side threaded adjuster until specified backlash is obtained.
If backlash is more than 0.20 mm (0.008 in.) repeat procedure from the beginning.

10. 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.).




11. Use a 12 inch caliper to measure between the inner most part of the holes (1 and 2) and compare between reading recorded in earlier step.
12. Subtract first reading from the seconding reading. Case spread should have increased 0.050 mm (0.002 in). If below 0.050 mm (0.002 in), increase torque evenly on both threaded adjusters and recheck backlash.
13. Install threaded adjuster locks and tighten the lock screws to 11 Nm (97 in. lbs.).
14. 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





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 specification.
4. Apply parking brakes lightly to create at 14 Nm (10 ft. lbs.) pinion rotating torque.

NOTE: If the axle is not in the vehicle, a large screwdriver can be used between the outer smooth edge of the ring gear and the axle housing to provide resistance.

5. Rotate the pinion/pinion flange 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 too far away from pinion gear, coast side toe (1) and drive side heel (2). Decrease backlash, by moving the ring closer to the pinion gear using the adjusters.





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





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





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





Pinion gear set too close to the ring gear. Increase pinion gear distiance, by increasing the pinion depth shim thickness.





Pinion gear set too far from the ring gear. Decrease pinion distance, by decreasing the pinion depth shim thickness.

NOTE: It may be necessary to adjust the backlash after adjusting the pinion distance.

SIDE GEAR CLEARANCE

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.