I have an S-crew 5.4 2004 4x4, 83,000 miles. I think from some research I have a 4R75E transmission but dont know for sure. It made a loud bang today while backing from a parking space under no extreme load whatsoever. Thought I'd backed into a car because the truck shuttered. No it backs slowly on level ground but will take no power/rpms without slippage. Forward motions and shifting is fine with no noise or whining. No fluid leaking or other visible signs. Does anybody have a clue? Thanks

 

To any who may search this issue in the future I am posting what I've found out since I didn't see any similar problems in my own search of the posts. The dealer says I have a broken reverse band. The price to replace the whole transmission with a Ford rebuilt one was $750 more than to overhaul my current one. Since the replacement comes with a 3yr/100,000 mile warranty and the overhaul is 1/12,000 I am obviously doing the replacement. Guess the problem is rare still don't know why it happened to me. Was backing up under minimal load when it happened.

 

Sucks man. Mine lost power to 3rd gear going down the highway randomly on flat road. They opened it up and both 3rd gear and overdrive bands were toasted. I also did the Ford rebuilt option. Strange problems these transmissions have sometimes...