# Rear axel id



## 66goatframeoff (Nov 8, 2011)

Bought a 66 LeMans 4 door parts car suprised to find a 10 bold posi under it but still can't find the letter codes without tearing it apart how can I tell the gear ratio ? 9783393 c166 only thing I can find.


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## 68GTO4004Spd (Jun 19, 2008)

You could spin the pinion one rev and count how many revs the left wheel makes. 3 1/2 times is roughly 3:55. Or you could take the pumpkin cover off and find the ratio stamped on the ring gear. In the pic 39 divided by 11 is 3:55 gear. Sorry site too slow for the pic to load, the stamp will be the first 4 numbers 39-11 GM 6 70 1


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## 66goatframeoff (Nov 8, 2011)

found ring gear stamp 14114 gm2 66e is it a 411 ? the math does not work out ?know its eaton 66 .thanx for the help.


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## 05GTO (Oct 6, 2004)

66goatframeoff said:


> found ring gear stamp 14114 gm2 66e is it a 411 ? the math does not work out ?know its eaton 66 .thanx for the help.


It may be a 2.93, (41 divided by 14)


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## 68GTO4004Spd (Jun 19, 2008)

spin the pinion and count the rotations, that will tell you if it 411 or 293 for sure


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