- Posts : 973
Join date : 2013-11-03
Location : Upstate NY
Why would you go through all the work changing gears when you have an open carrier? (non-posi) It sort of doesn't make sense and defeats the purpose of installing a lower gear.
Depending on the manufacturer of the gear set you purchase, you might have to replace the carrier anyway. The thickness of the ring gear is much different between the 2.73 and 3.73. Talk to the gear manufacturers reps, they should know all the little details like that.
Beware! If you've never done a GM gear swap, it's not as easy as just swapping out parts. I strongly urge you to get it professionally done or you might wind up breaking it.
You're probably better off simply changing out the whole rear end. It'll be bigger (8.5 inch), stronger, it's faster to change, easier to change, most likely will have disc brakes, and it removes any doubt to if you got the pinion depth set correctly. 1990s Caddys had as low as a 3.73 gear. Someplace on here I have a list of what cars have which gears along with the RPO/SPID codes. Stick with sedan rear ends. Wagon rears won't interchange.
1977 Impala Landau x1
1977 Caprice Coupe x3, Sedan x3
1978 Impala Landau x1, Sedan x2, Station Wagon x1
1978 Caprice Landau x1, Caprice Coupe x2
1979 Impala Coupe x2
1979 Caprice Coupe x7, Landau x4, Estate Wagon x1
1981 Impala Coupe x1
1983 Impala Sedan x1
1983 Caprice Sedan x1
1984 Caprice Landau x1, Sedan x1
1985 Caprice Coupe x1, Landau x3, Sedan x4
1986 Caprice Coupe x1, Landau x1
1987 Caprice Landau x1, Sedan x4
1989 Caprice Sedan 9C1 x4