I was curious if the 1991-93 Devilles have a limited slip differential or is it an open differential? I was curious because the 4.9 has a lot of torque to put through FWD and some manufacturers use a limited slip differential in FWD with high power (Nissan Sentra SE-R Spec V and Dodge SRT-4 come to mind)

No. It doesn't have a differential.

It does have a diff. It is in the passenger side deep inside near where the pass side axle comes out. just not like a rear wheel drive diff

Talk to Thrasher Engineering, they have a posi unit that is deisgned around the 4T60E for the SC 3800 Grand Prix.

No. It doesn't have a differential.

~ No Diff!? How does it move?

Skullman {:{}

It has a "transaxle" (transmission and differential combo). If you look under there, you won't see the conventional differential. Not sure when they switched. I recall my '85 Eldo still had one. I could be wrong but I don't believe the transaxle is "posi".

its not, its a one wheel wonder. There used to be a site(they had an add on here) that sold posi type diffs for these cars.

thanks guys