GM B-Body Forum, 77-79 Caprice/Impala Forum

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GM B-Body Forum, 77-79 Caprice/Impala Forum

A forum for all the owners and enthusiasts of General Motors B-Bodies from 1965-1996, but dedicated to the owners of 1977-1979 Impalas and Caprices. Join up now!

    rear axle ?

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    rear axle ?

    Post  dougc383 on Mon Mar 03, 2014 6:37 pm

    Will the the 94-96 B body rear axle fit into a 1985 caprice. And if so what rear gears did they come with and what is the bolt pattern
    Sweet Seventy9
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    Re: rear axle ?

    Post  Sweet Seventy9 on Mon Mar 03, 2014 6:52 pm

    Welcome to the forum!

    Yup, it'll bolt right in.  It's 1 inch wider than the other and has a 5x5 bolt pattern.

    Impala And Caprice Available Rear Gear Ratios
    Axle Ratio     RPO Code Ring/Pinion Teeth Application
    2.56     GM8        41/16                Std. Roadmaster LT1
    2.73     GU2        41/15                Std. Caprice L99 (exc. 9C1)
    2.93     GW9/GU3 41/14                Std. Caprice LT1 (exc. 9C1), Opt. Roadmaster LT1
    3.08     GU4        40/13                Std. Caprice 9C1/LT1 (Police), Std. Impala SS
    3.23     GU5        42/13                Opt. Caprice L99, Std. Caprice 9C1/L99 (Police)
    3.42     GU6        41/12                Std. 91-93 Caprice 9C1/L05, Std. 94+ Fleetwood w/V4P
    3.73     GT4        41/11                Std. 91-92 Fleetwood Brougham w/V4P

    *V4P = 7,000 lb. trailer towing package... look for a hitch.

    I hope this helps

    Last edited by Sweet Seventy9 on Mon Mar 03, 2014 6:59 pm; edited 1 time in total

    1977 Impala Landau x1
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    Re: rear axle ?

    Post  GM B-Body Forum on Mon Mar 03, 2014 6:58 pm

    Welcome to the forum! Yes it will fit, Im actually doing that swap in my car right now, i just posted a topic about it two days ago. Depends on what model it comes out of will determine the gear ratio, and other factors. All 94-96 impala ss's came with a 3.08 ratio, disc brakes, and positraction (rpo code G80) in a gm 8.5 10 bolt housing with a 5x5 bolt pattern. 94-96 caprice 9C1 came with disc brakes standard, positraction was optional, and three different gear ratios were offered, a 3.08, 3.23, and 3.42, also with 5x5 bolt pattern in a gm 8.5 10 bolt housing. 91-96 civilian models typically have 11" drum brakes and at least a 2.56 gear ratio, but i have seen them with the 9.5" drums, positraction was also optional. Most civilian cars came with the 8.5 10 bolt, but i do believe the 7.5 was still offered though i havent seen one, but i havent been under many 91-96 b-bodies to say for sure. Wagons also have the 5x5 bolt pattern while all other models have the 5x4.75 bolt pattern. All rear ends prior to 1994 have drum brakes, either the HD 11" drums or the standard 9.5" drums. If im not mistaken, i do believe that any model equipped with the HD 11" drums have a 5x5 bolt pattern, though im not 100% sure. Everything is interchangeable between all b-body models from 1977-1996 regardless of model or options. Your goal now is just finding one.

    1979 Caprice Sport Coupe, 400hp Vortec 350, Th350, GM 8.5 w/disc brakes, 3.90 gears Detroit Truetrac, 2.5" stainless duals w/ x-pipe, Dynomax race bullets.
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    Re: rear axle ?

    Post  dougc383 on Mon Mar 03, 2014 7:31 pm

    Thanks guys

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