Hi, searched extensively already.

Just wondering if there's a way to see what gear ratio a diff has? I have a couple of FD rear diffs laying around, and can't tell if they're from a Manual (4.10) or AT (3.90).

Thanks in advance.

 

Count 'em.

You'll just have to pop the cover off and count the number of teeth on the ring / pinion.


...oh, and don't forget to drain it first.

 

AT pinion flanges dont have counterweights, MTs do. If they have been changed out to fit the required driveshaft then nevermind...

 

you can jack up the rear of the car, put it in neutral and turn 1 wheel. Count the revolutions of the wheel and the driveshaft. It helps to mark the shaft. And there you go...