were all trans ams posi? ive got a formula with an open 2.73 and found a 91 trans am that someones parting out. would be nice if i could get a posi diff out of it

 

any help?

 

No they did not, in all cases. It was optional.

Don't rely on "codes" or the various "turn the wheel" BS or other half-wit "hints" at it. Observe the parts directly before laying down your $$$$. Take off the cover and look.

 

You don't mention what year your Formula is, so it could well be a 9-bolt (though 2.73 is a 10-bolt gear). If so, there's no swapping guts from the 9- to the 10-bolt, which is what the 91 would be. Check the 10-bolt sticky at the top of the page for more info.

JamesC

 

oh i know, i was planning on ripping the whole rear off of this donor car. and i was planning on taking the cover off, just wanted to know if i should get my hopes up or not