I have a 2005 GT Convertible. I am pretty sure I do not have a positraction rear end. I would definitely like to have one installed but do not know where to start.
I see choices with different spline numbers (31 seems to be most common) and 8.8 inch (also common). Is it safe to assume that my run of the mill Mustang has a differential that would accept a posi unit of those dimensions?

Does anyone have any recommendations? Absolutely interested in hearing what others have done.

 

2005 GT came with an 8.8" rear end, 31 spline axles, and the Ford tlok. So you have it from the factory (limited slip differential, posi-traction is the GM term for it and Ford calls it tlok)

 

+1 what Jim said. Go lay a set. You'll see.

 

Yes your car came with ford trak lok. If your only spinning one tire then your clutches are burned up. You can rebuild them or buy a new diff.

 

Ok, well, I learned something new today. Thanks for the help guys!

 

/case closed!

 

The diff clutches are known to burn out on cars with a little extra HP. The dealership will tell you that the carbon fiber ones will last longer. Maybe they do. Seems like they don't. It really depends on what you're plans are for your car, but if you plan to keep it or modify it, some guys (including myself) have switched to the gear driven LSD by Eaton. No clutches to wear out, it's quiet, holds a good amount of power and works great.

 

Get a eaton tru trac and never have to fix it again!

 

808 have you installed a eaton tru trac on yours yet. Im thinking about getting swapping out my rearend this spring along with a circle D converter. Im not sure how well stock rearends hold up to 1.55 60 times but I cant imagine not forever. Anyway I was just wondering if you did and if you liked it or not

 

It's what I have and so far so good. Sactown has one as well and he's doing 1.4 60's, launching off of a transbrake. I like mine.