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posi carrier interchange

Discussion in 'Chevy Trucks' started by msmit62, Jul 2, 2003.

  1. msmit62

    msmit62 Junior Member
    Messages: 5


    Need help guys! I have a 67 Chevy C-10 that I'm going to restore. It's all original including the rear end. I parted out a 73 Blazer, also original (very rusty), and it had a posi in the rear end. My question is if the 73 posi unit will interchange with the open rear end in my 67. They both have the standard GM 12 bolt axle (as least I know the diff covers are identical). Someone told me that 64-82 carrier units will interchange, but 2.76-3.42 ratios used one carrier and 3.73 used another carrier. If so, the carrier will fit, I'll just need a ring gear spacer. Also, are the splines the same? The axles out of the 73 have 30 splines, but I'm not sure about my 67. The truck is still together so I haven't taken the axles out yet. Thank-you!!! Email me at msmit62@yahoo.com

    Matt Smit
  2. snowjoker

    snowjoker Senior Member
    Messages: 283

    Welcome to Plowsite Matt:waving: I cant answer your question but there are alot of members that can. Do you have a plow truck? And if so what kind of set up do ya got?
  3. wyldman

    wyldman Member
    Messages: 3,265

    Welcome to Plowsite.

    The case,not the carrier is what you are referring to.The carrier is the actual axle housing.

    The cases are all the same for the 12 bolt,and will fit into any 12 bolt carrier,or housing.There are different cases for different ring gear ratios,but I can't remember off hand what the split is,but I'm pretty sure it was 3.73 and down,or 4.11 and up.If your ring gear won't work,then you may be able to use a spacer,or a special gearset to accommodate the carrier.I know they have lower ratio gearsets (4.11 and up) to fit the 3.73 and down case.The side gear\axle spline count should also be the same.Only way to know for sure is to open it up.
    Last edited: Jul 2, 2003
  4. wyldman

    wyldman Member
    Messages: 3,265

    I just double checked,and you were correct.The 3.73 and up uses a different case.

    So if both your ratios are less than 3.73,or both are 3.73 and up,then the case will swap right in,and you can use either gearset.

    If the ratios are different,and one is lower than 3.73,and the other is 3.73 or higher,then you will still be able to swap cases,but you will either need a ring gear spacer,a special gearset,or just use the ring and pinion that is already on the posi case.
  5. Alan

    Alan PlowSite.com Addict
    Messages: 1,393

    If the track width and spring perches are the same dimensions I'd just swap axles. 67 to 73, I'd bet they are.
  6. JohnnyU

    JohnnyU 2000 Club Member
    Messages: 2,040

    Didn't some of the 67-72's have coil springs and trailing arms though?
  7. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    Yes, in fact it was in the 62 - 66 models, and in the 67 - 72 models, 2wd's. I know the half tons had them, not sure about 3/4 and 1 tons.

    Of no help is that the 67 - 72 models were all 'C' according to the emblems (except the Blazer, it had a K/5 emblem).