How do you tell what size of differential is in a mustang. I have an 1988 GT Convetible auto and would like to know what size of differential is in it?

 

Jack the car up, not the rear end cause you want the rear end to be fully suspended. But there should be a metal tag on one of the cover bolts with some numbers. Write them down and visit a shop or auto parts store and they will tell you. If there is no tag then visit a shop and they will tell you, it might not be free!!!

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I looked and it should be a 8.8". Not sure though.

 

thanks! i found the tag and got the numbers.

 

GT has the 8.8" rear.