What gear ratio is this?

Discussion in 'Got gears?' started by 1969RIVI, Feb 22, 2020.

  1. 1969RIVI

    1969RIVI Well-Known Member

    Ok so I finally got around to cracking open this rear end I got with a parts lot. It came from a 88,091 mile 69 Riv GS. I know it's the 9 3/8 "big car" rear end and was told it was a 3.42 posi (still had posi tag) but can someone confirm the actual ratio?
     

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  2. flynbuick

    flynbuick Guest

    3.42 is correct once you round off 41/12.
     
  3. Bens99gtp

    Bens99gtp Well-Known Member

    Man, lots of broken cover bolts in that housing........those can be a pain
     
  4. 1969RIVI

    1969RIVI Well-Known Member

    Yeh, I had to cut the heads off with a grinder. Even though the rear was stored in a shop since 1992 the Canadian winters before that ate away at the hex heads and turned them into round heads lol. I was able to get the socket to grip onto 2 or 3 that's it!
     
  5. 455 Powered

    455 Powered Well-Known Member

    Clean around the ones that are still stuck. Give them a couple quick smacks with a hammer to loosen some of the crud around them. Then drip hot candle wax on them and go after them with a hammer and sharp punch or chisel on the outer edge to spin them out
     
  6. monzaz

    monzaz Jim

    Yep, Eaton Posi Spiders look good, gears look good.
    Remember that the driveside bearing is bigger than the passenger side
    this will be in all 1967-1970 Buick 9 3/8" full size car rears.
    We have clutches for the posi if needed
    Nice Find...
     

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