Differential ID mystery

Discussion in 'VIN, Trim Tag & Drivetrain Decoding' started by Fwyflier, Nov 8, 2019.

  1. Fwyflier

    Fwyflier New Member

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    This one as stumped me. I have a gen two rear end with the following ID, casting is 1235542 with an N on top, date code is 6154 and here is the weird part, it is stamped CG G196 2 G and it looks like it has a 3:42 posi gears (haven’t open it up yet). It is in a 1973 trans am. Obviously this is not the original rear. As far as I can tell casting indicates 8.5 10 bolt, date code is June 15 1974 however the only place I can find CG axle ratios are 1971, 72 which indicates 3:73 posi. I’m sure the gears could have been changed I’m just puzzled over the ratio stamp not showing up anywhere in 1974.
     
  2. Gary S

    Gary S Administrator Lifetime Gold Member

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    This site shows CG as a 3.73 non-posi used on 1974 Camaro. Firebirds used the same codes as Camaros so it is very likely that they also used the CG code in 1974. The rear end could have come from either a Camaro or a Firebird.
    http://nastyz28.com/camaro/camaro74.html#engine
     
  3. Fwyflier

    Fwyflier New Member

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    Thanks for that link. Every place I looked didn’t have those 1974 codes
     
  4. CamaroNmotion

    CamaroNmotion Veteran Member

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    The last letter G in post #1 stamping indentifys it as a POSI rear. (G = chevy G & A posi carrier for 1974).
     

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