The carrier bearings are pressed on with about 8 tons of force-Nick prefers to do one at a time, though both can be done at the same time. Once installed, the ring gear and posi can be slipped into the rear, tapped into position with a mallet, and the 7/16-inch carrier bolts torqued to 65 lb-ft. | 
Setting up the ring gear is always a trial-and-error process to get the backlash just right. On the first go-round, it's too tight (left to right) and is binding up; new shims are used to rectify the problem. Matt Sorian adds a .002 shim to the right side, and removes one from the left. By wiggling the rear left to right, and using a feeler gauge to measure, backlash is determined to be .009, which is as close to perfect as you can get. |  |
The wear pattern is checked using the provided marking fluid and brush, which determines the front/back orientation of the ring-and-pinion. If the wear pattern indicates misalignment, the ring-and-pinion have to come all the way off-this is why gear installs can be time consuming and pricey when not done right. Thankfully, that wasn't necessary, as you can see the wear pattern is dead center with a slight bias inward. | 
The carrier bolts come back out and are replaced by the studs in the TA Performance kit, which are treated with red Loctite and torqued with a 3/16-inch Allen wrench to 10 lb-ft. Meanwhile, the 11/16-inch nuts are torqued to 65 lb-ft. | 
While some axles are different lengths and side specific, these are not, and can be slid into the tubes and jiggled a bit (not hammered) to get into position now that the C-clips have been removed. A magnet is used to put the stock C-clips back in and then the axles are tugged outward to lock into place. The pin also goes back in, and red Loctite is placed on the 8mm retaining bolt (not much force or torque is needed to tighten it down). |
Nick prefers to use GM sealant on the TA differential cover, discarding the provided gasket, and GM pipe sealant is used on the bottom drain plug (the top fill plug is left out for now). | 
The two longer studs in the kit go just above the center bolts because that is where the brake line brackets are mounted. Sealant is placed on the center bolts, as past experience has taught Nick that these tend to leak otherwise. A 1/4-inch Allen wrench is used to tighten the studs with 25 lb-ft and 60 lb-ft on the center studs, which are locked into place with a 7/8-inch wrench tightening down the nuts. | 
Per Eaton's instructions, mineral-based 80W-90 differential fluid is used along with a posi additive to maintain the integrity of the clutches. After dumping in about 3.5 quarts, the 3/8-inch fill plug is tightened down, and the Formula's rear is all buttoned up. |