Part 4: Working on the Rear Diff

If you are replacing the ring and pinion, file any burrs on the face(flat side) of the ring gear that may keep it from resting flat againstthe differential. Also, lightly chamfer the inner edge of the ring gearwith the file (just enough to remove the sharp edge). Using the suppliedbolts, we bolted the ring gear to the carrier (remember, the bolts areleft-hand thread.) Apply LockTite to the threads and torque to 55 lb-ft.

To press the bearing onto the carrier, we used a piece of thin-wall pipe(ours was an old round-style jackstand with a removable center thathappened to be the same size as the inner bearing race). When installingthese or any bearings, make sure you apply pressure to the bearing race,not the basket or cage.

With our casing cleaned and painted, we installed the pinion races. Ifyou do not have a bearing and a race installer, use a brass punch toseat the race into the pinion bore without damaging it.

We used the same piece of jackstand to install the larger bearing ontothe pinion gear. If your old pinion had any spacer washers, replace thembefore installing the bearing. Hopefully, this will get you close to theright depth setting on the gear. Ours had no spacers, so we hoped forthe best.

Since we don't often do this, and we didn't have a pinion depth gauge,we'll show you how to set up the gears without one. Put the pinion gearin the housing, then install the front (small) bearing (be sure to oilthe bearings before you install them). When the bearing is far enough onthe pinion shaft to start the yoke nut, tighten the nut to 240 lb-ft. Ifyou have the proper bearing preload, you should have some resistancewhile turning the yoke with a torque wrench. A new bearing should be setat 20-30 lb-in, while reused bearings are set to 0-15 lb-in. If it istoo tight, add shims. If too loose, remove some.

Install the carrier into the housing to adjust the backlash. With thecenter section in the housing, install both bearing caps in theiroriginal location (you did mark the caps, right?). Snug the cap boltsfinger tight only. Put the bearing adjusters (arrow) on each side andhand tighten to remove bearing endplay. You may need to tap the bearingcaps with a small hammer to align the threads for the bearing adjusters.Now torque one bolt on each cap to 85-90 lb-ft. Mount the dial indicatorand magnetic base to the gasket face of the housing and let theindicator contact the ring gear directly on any tooth face. Tighten bothbearing adjusters equally until .0005-. 0015-inch backlash* is achieved.Next, install the bearing adjuster lock on the bearing cap on the sideopposite the teeth of the ring gear. Now, turn the gear side adjusterone hole at a time until backlash* measures between .006 and .008inches. Tighten the other two bearing cap bolts to the same torquespecs.*Backlash is the distance measured when you move the ring gear back andforth until it touches a tooth on the pinion gear without moving thepinion gear.

After applying marking compound to the ring gear, you can see that thepattern is not where it should be. This pattern means we needed to addpinion shims. This is solved by tearing it all apart and adding theshims between the big bearing and the pinion gear. When adding spacersunder the big bearing, include the same thickness spacer washer(s) underthe small bearing to maintain proper bearing preload. When you get thispattern correct, you are ready to install the casing into the rearhousing. Next, replace the axles and the brake assemblies and installthe proper lubricant to complete the job.

Since our rearend had been sitting idle for a good while, the brakeassemblies rusted, so we contacted Performance Suspension Technologiesand ordered new brake drums, shoes, and wheel cylinders. PST also hasall the springs and retainers needed. Remember, when you install brakeshoes, the longer shoe goes on the rear of the assembly. Also, make surethe brake adjuster is in position so you can turn the star wheel downfrom the outside of the backing plate if you need to.

We didn't want to reinstall rusty brake lines, so we contacted The RightStuff Detailing in Columbus, Ohio. The lines fit great with minimal"creative maneuvering" required.