Fox T-Bird/Cougar Forums

Technical => Drivetrain Tech => Topic started by: FENRISUNCHAINED on May 29, 2005, 03:26:35 AM

Title: Differentiating differences in differentials...
Post by: FENRISUNCHAINED on May 29, 2005, 03:26:35 AM
The rear end of my '85 is toast. I have an opportunity to pick up a '91 3.8 for cheap, but I need to know if it is a direct swap on the rear ends.

Thanks in advance.
Title: Re: Differentiating differences in differentials...
Post by: Haystack on May 29, 2005, 08:28:50 AM
what car is the 91 out of, If it is out of a t-bird/cougar, it is most likely a waste of money. You can get one off of a mark VII(1 1/2" onger) a mustang(About 1 1/2" shorter) But you will have to mesure your rear axel. In 1985 the rears went from the mustang width, to its own width. So it oculd be either a mustang or later t-bird/cougar rear end. Either way it should fit okay. Here is everything that you will want to know.
http://www.coolcats.net/tech/general/axleinfo.html
Title: Re: Differentiating differences in differentials...
Post by: Thunder Chicken on May 29, 2005, 08:41:15 AM
The '91 rear end is completely different. 89-97 T-Birds and Cougars had an independent rear end, while your '85 has a "solid" rear.
Title: Re: Differentiating differences in differentials...
Post by: Haystack on May 29, 2005, 09:01:04 AM
yeah that is what I ment.