12 1/4 Inch Ring Gear

ASSEMBLY

1. Place new pinion bearing retainer gasket on retainer and install pinion assembly in carrier. Pinion assembly should be pressed into carrier to prevent damage to shims.
2. Install pinion bearing retainer bolts and lockwashers, torquing bolts to 165 ft. lbs.
3. Lubricate differential bearing rollers with engine oil and place outer races over bearings.
4. Install differential assembly in carrier and install adjusting nuts. Carefully slide adjusting nuts alongside bearings so that threads on nuts fit into threads in carrier.
5. Install differential bearing caps, ensuring that marks made during disassembly are aligned.
6. Install bearing cap bolts and lock washers and tighten until lockwashers just flatten out.

BACKLASH & PRELOAD ADJUSTMENT

1. Loosen differential bearing cap bolts just enough so that bearing adjustment nuts may be turned with tool J-0972 or equivalent, then remove all lash between ring gear and pinion.
2. Back off lefthand adjusting nut one to two notches to a locking position.
3. Tighten righthand adjusting nut firmly to force differential into solid contact with lefthand adjusting nut.
4. Back off righthand adjusting nut until free of bearing, then retighten snugly against bearing.
5. Tighten righthand nut one to two additional notches to locking position.
6. Mount dial indicator on carrier and check backlash between ring gear and pinion.
7. If backlash exceeds .012 inch, loosen righthand adjusting nut one notch and tighten lefthand adjusting nut one notch. If backlash is less than .003 inch, loosen lefthand adjusting nut one notch and tighten righthand adjusting nut one notch.
8. Torque bearing cap bolts to 205 ft. lbs.
9. Install side bearing adjusting nut locks and torque to 15 ft. lbs.

RING GEAR THRUST PAD ADJUSTMENT

1. Inspect bronze tip of thrust pad for wear, replacing as necessary.
2. Install thrust pad and tighten screw until bronze tip engages back face of ring gear while rotating gear.
3. Back off screw 1/12 turn and torque locknut to 135 ft. lbs. Ensure that screw does not turn during locking process

CASE & DRIVE PINION INSTALLATION

1. Clean out axle housing and cover and install new gasket on axle housing.
2. Assemble differential carrier to axle housing, then install lockwashers and bolts, torquing bolts to 85 ft. lbs.
3. Install axle housing inspection cover, if removed, with new gasket.
4. Assemble rear universal joint.
5. Install axle shafts. Refer to individual truck chapters.
6. Fill axle to bottom of filler hole with suitable lubricant.