I just wanted to update this thread with the Eaton Part Numbers to rebuild various Eaton Posi Units. This includes the Eaton 8.2, Eaton 8.5 (Not the Factory Posi Units with the square tabbed clutch discs) and the Eaton 8.875.
Eaton 29403-00S ~ 18 steel discs, guides, and shims. This is what the factory used.
Eaton 29590-00S ~ 400 pound preload Spring Pack. This is an upgrade from the Factory 200 pound preload Spring Pack. All new Eaton Posi Units are manufactured with the 400 pound Preload Spring Pack.
Eaton 12 Bolt (8.875) Casting Numbers:
EDB-32088 ~ 2 Series Posi ~ 2.73:1 and down
ED-30140 ~ 3 Series Posi ~ 3.07:1 - 3.73:1
EDB-30174 ~ 4 Series Posi ~ 3.90 :1 and up
The 12 Bolt (8.875) Posi Units use the following:
YSPXP038 ~ Cross Pin
YSPBLT-065 ~ Cross Pin Bolt
Please note that some aftermarket 3.90 gear sets are made for the 3 Series Posi Unit.
Eaton 10 Bolt (8.2) Casting Numbers:
ED32118 ~ 2 Series Posi ~ 2.73:1 and down
EDB30116 ~ 3 Series Posi ~ 3.08:1 and up
The 10 Bolt (8.2) Posi Units use the following:
YSPXPG8.2-P ~ Cross Pin
YSPBLT-066 ~ Cross Pin Bolt
Disassembling the unit and inspecting the individual components is critical to reading the actual condition of the Posi Unit. You have to have the clutches out where you can view that actual wear surface. Dark gray to black is good as long as there are still visible grooves in the surface. If there is a shiny tint towards the center of the clutches with a dark outer ring, then there is about 50% life left. If the clutches are shiny across the entire surface, then they need to be replaced.
Regarding the GM Corporate 8.5 Posi Units that use the square tabbed clutch discs, GM discontinued the rebuild kit in 2009. I am now reproducing the kits.
For information on the 8.5 Posi Clutch Disc and Shim Kit, please send me a PM.