We are proud to announce that we are offering Supplemental Rebuild 8.5 Posi Kits. This new kit features a new 300 Pound Preload S-Spring, Cross Pin, Cross Pin Bolt Thrust Washers and C-Clips. These kits fit the GM Corporate 8.5 Posi from 1971 - 1987 and the Oldsmobile Type "O" Differentials from 1967 - 1970. You will not need the C-Clips for the O Type 12 Bolt Rear Differential because of the Bolt In Axles. If you have a 12 Bolt Olds, please contact me before bidding and I will adjust the price by removing the C-Clips from the kit. The casting numbers for the posi units this kit fits are 410408, 410409, 671, 672, 673, 725, 726 and 588. As a point of reference, the spider gear in the posi unit is GM Part Number  6270977. I just want to give everyone as much information as possible to verify that this kit is correct for their application. Please note, to avoid confusion, the spider gears are not included in the auction. 

Also included is a bottle of GM Limited Slip Additive, GM Part Number 88900330.

Everything in the photos are included in the auction, To clarify, this kit includes:

1 ~ 300 Pound Preload S-Spring

1 ~ Cross Pin

1 ~ Cross Pin Bolt 

2 ~ Thrust Washers

2 ~ C-Clips

1 ~  GM Limited Slip Additive, GM Part Number 88900330

This kit will fit 1971 - 1981 Camaro,  Z/28, Firebird and Trans Am ( F Body ), 1984 - 1987 Grand National and Turbo T-Type Buick, 1984 Hurst Olds, 1985 - 1987 Oldsmobile 442, 1971 - 1979 X Body Nova, GTO, Ventura, Omega and Apollo. Below is a list of additional applications for this kit:

I am now offering a posi unit rebuild service for 50 dollars. Please send us your 8.5 GM Posi Unit and we will install the new clutch disc and shim kit. If the winning bidder decides to use this service, round trip shipping is the buyer's responsibility. I will send you a prepaid UPS Label that you just have to tape to the box. Drop the box off at any UPS location or simply give the box to the UPS driver. If there are any other broken parts in the unit (Side Gears, Spider Gears, Cross Shaft, etc.), the buyer is responsible for the cost of the new parts. The labor rate will remain the same. I can also install new carrier bearings for the cost of the bearings or send the bearings with your posi unit and I will install the bearings at no charge. Please contact me for all details.

If anyone is interested, Steel Clutch Disc and Shim Kits are also available for the 2010 - 2015 Camaro SS. This kit will replace GM Part Number 92230606.  

8.8 Ford Posi Traction Lok (Traction Lok) Steel Clutch Disc and Shim Pack Kits are now available. This comprehensive kit is a direct replacement and upgrade for Ford Racing FMS-M-4700-C.