Re-Rearing A T/A

1. When last we visited our 10-bolt, we were in the process of determining the pinion depth. Our final measurement came up as 2.550, when we needed 2.600, which means that the pinion would be too close to the pinion gear when installed. We decided to leave the .035 shim from the factory pinion in place and to double check by installing the ring gear on the carrier and checking the pattern on the ring gear, per Randy's instructions.

2. Here is our ring gear fresh from Yukon Gear by way of Randy's Ring & Pinion. It's a 3.42 ratio with 41 teeth on the ring gear and 12 on the pinion. Divide the numbers and 3.42 is the result. The number 360 is also found on the ring gear and the pinion gear to identify them as a matched set.

3. It's cheap insurance to install the new ring gear bolts prior to installing the gear. One, you can make sure that they thread in easily and, two, you can check to make sure that they aren't too long to properly seat the ring gear to the limited-slip unit. Here the bolt height from the bottom of the head to the ring gear surface is measured by Papo Concepcion.

4. Then the thickness of the flange of the limited slip unit is measured. Our bolt length was fine.

5. Note that the inner ring gear flange is chamfered to avoid galling the limited slip unit. Should metal be picked up by the gear during installation, it will get trapped underneath the ring gear and it won't fit flush to the case. Also, note that the bolt holes are chamfered to eliminate raised sharp edges.

6. Prior to installing the ring gear, make sure that its surface and the carrier flange are perfectly clean and smooth. Though some builders recommend pressing the ring gear on to the carrier, we were able to install ours by tapping around the edges with a rubber mallet with no trouble. Just be sure to line up the bolt holes correctly to avoid cross-threading the bolts.

7. Once the gear was close enough to get a few bolts in, they were installed and the gear was drawn up to the flange by tightening the bolts in a crisscross pattern. Then the bolts were removed and Loctite was applied before they were reinstalled. See this? It's wrong, according to the Powerhouse video. It says that you should put the Loctite in the bolt hole not on the bolt. This way it won't seep under the ring gear

8. Finally, the ring gear bolts were torqued to 70 lbs.-ft. This photo is a mock up. I locked the housing in a vise to do the actual tightening.

9. After all of this work, the ring gear and pinion will be reunited. The carrier, outfitted with lightly oiled bearings, bearing races and the same shim packs with which it was removed, is lifted into the housing.

10. It is important to reinstall the shims that you removed during disassembly on the same sides for reassembly. Also, the unit should not easily drop into place. It should be tight with the shims installed so that the ring gear can't move from side to side during operation. As it turned out, we needed to juggle shims from side to side to properly place the ring gear in relation to the pinion. The smaller increment shims that were provided by Randy's Ring & Pinion replaced some in the thicker factory shim pack in a like amount to make small side to side adjustments easier. When all was said and done, it took a .021 shim pack with a .186 spacer on the driver's side and a .015 shim pack with a .105 spacer on the passenger side to get a snug fit for the carrier and the proper backlash on the ring and pinion.

11. The carrier caps are torqued to 60 lbs.-ft.

12. Backlash is checked with the dial indicator placed at 90° to the gear tooth. The recommended amount is .008-.012 as marked on our ring gear. According to Randy, a general rule of thumb is that for every .010 that the ring gear is moved left or right via changing shims from side to side, the backlash changes .007. Moving the gear closer to the pinion decreases backlash while moving further away increases it. Ours is .009.