Rear Diff Question
 

How do i know what size rear end i have? I need to order a differential, and there is many sizes of rear's to choose from. For example:
GM 7-1/2'' & 7-5/8'' 10-Bolt, 26-Spline?
GM 7-1/2'' & 7-5/8'' 10-Bolt, 28-Spline?
GM 8.2'' 10-Bolt ''C'' Lock, 28-Spline?
GM 8.5'' & 8.6'' 10-Bolt, 28-Spline ?
????????????? :crazy:
The truck is an 86 1/2 ton, and has 3.08 gears. Thanks alot.

Well if it is still original, you have an 8.5" 28 spline. What are you looking for as far as a posi unit, I have an original equipment one that I wold sell you for $140 to your door.

info
 

7.5" -26 spl-vega, chevette,78-86 el camino-camaro-malibu-monte carlo (g-body) s-10
7.625-28 spl-87+s10, camaro, firebird, blazer (s10)
8.2 "c" 64?-74 chevy bodied cars
8.2 "B",or "O" buick or olds rearend-bolt in axles-limited parts availibilty
8.5 most popular "corporate" axle-found in camaros 70.5-81, impalas, chevy trucks up thru 95? or beyond. could be had 5.75 bolt pattern (camaros). 5x5 bolt pattern (impalas, trucks) 6x5 bolt pattern (2wd blazers).
warrens69gmc