quigman

Hey guys, noobie here
Which if any of the 7.5 diffs come with a limited slip. I live in Tucson Az and am having a hard time finding one. I am in the planning and part collecting phase of the build. Any help would be appreciated.

tbone heller

I acquired a new Ford Tracloc differential to install in mine. It was around $250.00. I always replace all of the bearings & seals on any rear end that I get from a junk yard because they are usually JUNK. Any limited slip unit that you find will most likely have worn out clutches anyway.

quigman

Thanks for the response. I went to the salvage yard today. They had no less than 10 to choose from but none had an lsd. I figured I will have to buy a unit and install it. I was trying to be cheep and lazy.

MRM331

They seem to be a bit more prevalent up here in the North East than down your way. To find one here is what I do.

1. Cruise the junk yard for Thunderbirds and Cougars.
2. When you find one check the door pillar for an "E" printed where it says "axle" on the build plate. An "E" means the car came with a differential a 7.5 with limited slip. "5" is the most common. This is a open 7.5.
3. To verify that the diff was not swapped at some point go under the car and look at the back of the differential. It should have a "7.5" cast into it. Next, take a wrench and reach up and pull out the top rear bolt holding the rear cover on. The diff tag is attached to this bolt. Take it out and read it. If it says "3L27" its the diff you want. If it says "3 27" its open.

Keep in mind that the factory Thunderbird limited slip is in no way the best one in the world. You'd end up with a much better end result if you picked an open one and installed an aftermarket unit.

-Jason

charchri4

Jason if we go the open diff route with plans of putting in a trutrack is there any reason we could not use 6 cyl bird diff?

MRM331

As far as I know all 7.5 differentials are in 3.8 litre V6 Thunderbirds. The V8's and supercoupes had 8.8's.

Keep in mind that we are talking about only generation 10 Thunderbirds/Cougers (1989-1997). All earlier ones had a live axle and the later retrobird had something completely different.

-Jason