I have a 93 F 150 XLT, I just rebuilt the Transfer Case thinking that was my problem, well it wasn't. The truck shifts smooth, no tranny noises, but when I engage the clutch to shift gears the rear wheels lock up and the passenger side rear actually turns in reverse. I can start the truck in or out of gear with the clutch engaged, but I can not shift gears while moving because of the lock up. Not sure what the issue is but any feedback would be nice.

 

I would pull the cover of the rear diff and see if there's anything goin in there.

 

Yea I'm thinking the same thing, just doesn't make sense. I am in the process of checking that now. I will update if I find anything.

 

thats what i would do.

 

My buddy had something similar happen with his old Chevy. The rear locked up three times. Turns out a ring gear bolt came loose and got between the ring and pinion. He would back up and it would unlock. Tryin to get it home it happend three times until the gears cut the bolt in half a and spit a piece through the cover.