So did my first drive in my new monster and think my fiff broke not sure all i know is i would try and drive forward and hear a clanking from rear end sent it back to the shop to be checked out. I got it from a junk yard and filled it with new royal purple csr runs great other than that. I tried several gears so can be the tranny felt like comming from rear wheels and rear end made a loud clunk when pulling it on a flat bed. Any sugestions. Also i found a bunch of 27 spline 7.5 track loks for sale online for 200. they say they are use in stangs.
http://www.cjponyparts.com/product.a...paign=shopping

 

It was the axle had the car to low.

 

I was going to add that not having your driveshaft flange yoke bolts tight at the differential pinion can also make a pretty pronounced clunk.

Make sure the track locs will work in an independent rear pumpkin as well as a live axle like a Mustang has.

-Jason