D ifferential Case

b. Install differential w ithout ring gear and check runout of differential case flange. If runout is more than .002", the defect is probably due to bearings or differential case. If flange runout is less than .002" the ring gear was probably at fault. Correct the defect before proceeding further. 6. If runout is saftisfactory (less than .002"), remove indicator and determine shim thickness necessary for differential side bearing preload as follows: a. Insert a pry bar between carrier and bearing on end housing half of case to move carrier as far as it will gob. Measure clearance between carrier and bearing at end housing half of case by inserting long feeler gauges all the way across outer face of bearing. W rite down total feeler gauge thickness (For example: .054"). Remove feeler gauge. c. Insert pry bar between carrier and bearing on ring gear flange half of case to move carrier until no backlash can be detected between ring gear and pinion. d. Measure clearance between carrier and bearing at ring gear flange half of case by inserting long feeler gauge all the way across outer face of bearing. W rite down feeler gauge thickness. (For example: .036"). e. Remove differential assembly from carrier and remove differential side bearings. f. Install shim packs as follows:

NOTE: If old shims are to be reinstalled make sure nicks in shims caused by bearing puller are placed to line up with notches in the case.

1. A t ring gear flange end of case, install shim pack equal to amount gauged in Step d, above (example: .036"). Install bearing tight against shim. 2. Subtract the am ount of shims installed (example: .036") from the am ount gauged in Step b, above (example: .054:). To the result (example: .054" .036" .018") add .015" to .020" shims to provide bearing preload. 3. Install the shim pack determined in Step (2) above (example: .018" .015" .033") at end housing half of case and install bearing tight against shim.

In sta llin g D iffe re n tial

1. Using dial indicator and Tool J-5231-01 again, as when removing and installing differential, spread carrier not more than .020". 2. Install differential bearing cups and set differential in carrier. Rotate differential and tap ring gear with a soft ham m er to assure bearing seating. 3. Install differential bearing caps in their correct locations as indicated by marks made at time of removal.

Tighten bolt slinger tight. 4. Release pressure on spreader tool and remove; tighten bearing cap bolts to 80 ft. lbs. torque. 5. Install dial indicator and check ring gear to pinion backlash at four equally spaced points around ring gear.

Backlash must be between .003" and .006" and must

not vary more than .002" between positions checked. If backlash is not within these limits, change the differential bearing shim pack at both bearings to correct. Total of both shim packs must remain the same. 6. Check ring and pinion tooth contact pattern, using red lead and oil as outlined in Section 4. 7. Install new gasket on carrier and install cover. Install metal ratio tag under one of the cover bolts. Tighten bolts evenly and alternately. 8. Install axle shafts as outlined previously. (Refer to

Truck Chassis Service Manual, Section 3).

PINION AND B E A R IN G S

Rem oval and D isa sse m b ly

1. Remove pinion flange, oil seal, gasket, and oil slinger.

Use Tool J-8614 to hold flange. 2. Remove differential as outlined in preceding pages. 3. Tap drive pinion and inner bearing cone out of carrier, using a soft hammer. Tag and save shim pack on splined end of pinion (outer bearing shim) for reference during assembly. If ring gear and pinion are to be replaced, write down the markings plus, minus or (0) on face of pinion for reference during assembly. 4. Remove pinion outer bearing cone from carrier. 5. If pinion bearings are to be replaced: a. Remove inner bearing cup, using suitable drift, and driver or slide ham m er to take cup out of carrier. Tag and save shim pack for inner bearing cup for reference during assembly. b. Remove outer bearing cup from carrier, using a suitable drift or punch. c. Press pinion inner bearing cone off pinion using J-8553 and remove oil slinger from pinion.

A sse m b ly and Installation

1. Install oil slinger and new bearing cone on drive pinion, using J-5590 to seat outer bearing against shoulder. 2. Install outer bearing cup in carrier, using Tool J-6368 with driver handle J-8092 to seat cup in counterbore. 3. If a new ring gear and pinion are to be installed, note the "plus" or "minus" markings on the rear face of the original pinion. These markings represent the variation from the nominal pinion depth dimension to obtain the proper tooth contact for individual gear sets.

The approximate depth setting of the new pinion may be made by increasing or decreasing the shim pack next to the pinion inner bearing cup to correspond with the difference in markings on old and new pinions.

To maintain proper pinion bearing preload, shims must be added to or subtracted from the pinion outer bearing shim pack to correspond with changes made to the inner bearing shim pack.

If the difference in the markings on the old and new pinions is in the "plus" direction, shims must be removed from both pinion bearing shim packs. If the difference is in the "minus" direction, shims must be added.