my buddy bought a set of gears and an auburn for his 93 1500 with the 8.5 inch, never installed it, he has the install kit.... i know we have the 8.6 but it'll fit. question is... which install kit do i need? will the install kit he has... fit? by install kit i mean bearings/shims.

 

Unless it is the Pro series Auburn pn-542052 or the high performance series 542097(NOT the high peformance series- 542022), it will not work in your truck. The bearing hub size is different, and there is no bearing to make the early case work in a late truck. Also, if it is the proper Auburn, his install kit will have the wrong carrier shims and bearings.