I had my transmission rebuilt. 7.3, 4R100 After it was rebuilt it failed with in 200 miles. The cause of failure was the intermediate clutch between 3rd and 4th. Second failure Then It wouldn't go in reverse unless you left your foot off the fuel pedal. Then it would idle in reverse and if you gave it more fuel it acts like the brakes are on. Failed in less than 100 miles intermediate clutch failed again. Fixed and still acts the same reverse feels like a brake is on. The transmission shop has no Idea what is going on.
I ran into a similar problem, I ended up replacing the main valve body, and acculator valve body also the 1-2 accumlator valve was sticing causing forward, intermeadiate and reverse clutches to fight each other the good thing is 4r100 valve bodies are mostly all interchangable which makes them cheap
April, 12, 2013 AT 4:25 PM
I would have another shop check this for you. Sounds like they are out of ideas