I have an 02 Ram1500 4x4 and just put a Detroit Locker in the rear. Now I notice when I leave a stop or just punch it while driving, it seems to free rev before it goes. I went ahead and changed the tranny filter and fluid again (it needed it) and it seemed to help a little.I don't know if these are just the characteristics of the locker or signs of a failing transmission. Any advice would be greatly appreciated.

 

I can't imagine changing the diff could cause a transmission failure like the one you are describing. I would think it's a coincidence or maybe the installer somehow caused some damage.