Positraction Install

Carbon Inside
Eaton Posi Performance Differentials feature a patented carbon friction material originally designed for racing brakes and clutches. Made from high-temperature carbon fiber wrapped with a carbon anti-wear coating, the discs are virtually indestructible, Eaton claims. And despite repeated hard use, there is no loss of performance. Eaton's warranty says that the patented carbon material provides smooth, quiet operation over the life of the vehicle.


To install a Posi, you'll first need to disassemble the stock rear end. Start by putting a drain pan under the differential and draining the oil. Remove the cover plate's bolts and carefully remove the cover plate. Then remove the disc brake calipers and parking brake drum. Be sure to mark the bearing caps with punches. It is very important that these caps go back in on the correct sides and that they are not upside-down.


After removing the pinion shaft retainer bolt, slide out the pinion shaft which holds the spider gears in place. Then remove the axle C-clips and pull the axles out about a foot. When pulling out the old differential, note the carrier bearing shims located on each side. These go between the bearings and the housing. Remove the bolts holding the ring gear to the differential, and with a punch carefully tap it loose. Next, tap the ABS ring off.


Using a bearing puller remove the old bearing and the race. This is a new 8.8 so we will reuse the bearing and the race. From there, you can install the Posi, as illustrated in the accompanying captions and photos.


We were very impressed with the new limited slip. After installing it in a '39 Ford pickup with a custom chassis, we took it out on both dry and wet pavement and the unit worked perfectly. It really made a big difference in the performance with both wheels hooking up when the power is applied.