Are there any number or letter markings on the rear housing. Also how would I read them ? I have a 75 coupe, 4 speed and it was listed as a 3.70 rear when I bought it. I'm not really sure that is correct. I think it was changed to a higher number rear. Any help would be greately appreciated.

Thanks, ACE

Ace,

The code is located on the bottom of the differential carrier housing by the cover. Example: OA W2131

OA=3.08 ratio w/positraction

W=Plant

213=213th day of year

1=first shift D=day N=night

OA=3.08, LR=3.36, OB=3.55, OC=3.70

Plants...C=Buffalo,G=Chevrolet gear & axel, K=GM of Canada, W=WarrenThis should do it for you..Terry in Alaska

  Thanks, I'll check it out tomorrow and see what I find. Nice ride you have there also.

ACE