3.73 Posi rear end in 1994 Fleetwood Brougham
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RWD 19xx-1984 DeVille and Fleetwood,
1985-1996 Fleetwood and Brougham Forum Discussion, 3.73 Posi rear end in 1994 Fleetwood Brougham in Past Cadillac Vehicle Discussion; Hello everyone! Im seriously interested in putting 3.73 gears in the rear of my Lt1 fleetwood, but i want posi ...
  1. #1
    smf
    smf is offline Cadillac Owners Fanatic
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    Question 3.73 Posi rear end in 1994 Fleetwood Brougham

    Hello everyone!

    Im seriously interested in putting 3.73 gears in the rear of my Lt1 fleetwood, but i want posi too while im at it. So what do I need?? I here that I can take a posi rear end out of several various GM trucks on the 1500 frame and swap it. But What if I want to buy new? Is there a good part number on what I need? Just the pumpkin or the whole rear? Prob a better question for an Impala Ss forum I know. . . But any help from my Cadillac gurus is greatly appreciated!! Thanks!

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    drugthug69 is offline Cadillac Owners Member
    Automobile(s): 96 Fleetwood Brougham stock and mint
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    I need to know this too! I dont have a specific plan for this, just because I need more knowledgeable input on what would make sense enough. Being in California I dont want my car to be unsmoggable after a mod that does nothing bad but still burps out bad codes.

  4. #3
    smf
    smf is offline Cadillac Owners Fanatic
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    Re: 3.73 Posi rear end in 1994 Fleetwood Brougham

    Bump

  5. #4
    csbuckn is offline Cadillac Owners Master
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    A rear end from a caprice is the direct bolt in except the e-brake. 3.73s are harder to find in stock form. Your best bet is to find a caprice(box or bubble) cop car and get the rear end. Not all cop cars had posi but most did. Some cop rear ends will be abused also so you gotta open the rear end up and look at the pin. Most bubble caprice wagons will have a posi carrier but the actual rear end itself is too long. You can take the posi carrier out of the wagon rear and put it into an open 8.5 rear end but that requires you to know how to rebuild a rear axle.

    I'm not sure about the truck rear end that you mention being a bolt in, never seen anybody fit a truck rear under a B or D body. Trucks may have a better chance of having 3.73s but the posi is different, they usually have some sort of locking differential that might be rougher riding then the limited slip posi in B and D body cars. I don't know how much rougher or if you'd even feel it.

  6. #5
    rodnok01's Avatar
    rodnok01 is online now Cadillac Owners Connoisseur
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    Truck rearends more than likely won't fit. Usually wider and mounts are different. Also bolt pattern may be different.
    If you are going to the trouble of setting th e rearend up by swapping parts new bearings, seals would be advisable.

  7. #6
    csbuckn is offline Cadillac Owners Master
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    Re: 3.73 Posi rear end in 1994 Fleetwood Brougham

    Do the bubble lacs have 8.5" rear ends? If so, you can just buy a posi carrier and 3.73s for your rear end and install it.

  8. #7
    shrike77 is offline Cadillac Owners Fanatic
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    Re: 3.73 Posi rear end in 1994 Fleetwood Brougham

    There was one year that Fleetwoods came with 3.73 with the towing package. I think it was 1993, not sure

  9. #8
    smf
    smf is offline Cadillac Owners Fanatic
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    Re: 3.73 Posi rear end in 1994 Fleetwood Brougham

    Anyone know the rpo code for caprice with 3.73?

  10. #9
    jayoldschool's Avatar
    jayoldschool is offline GM RWD V8 addict
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    There was no caprice with 3.73s. The 93 Fleetwood with trailer package was the only one. Just Google 3.73 RPO and you'll find the SPID code ( I'm on my phone).

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