The gear ratio should be stamped on the flat surface of the back of the diff, where the cover bolts on. It will be an area where the diff housing is wider than the cover with enough room to stamp numbers about 1/4" tall.


Then there is the old standby of jacking up one side, turning the wheel one turn and counting the driveshaft revolutions....and multiply by two.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.