New to the forum. Have a 92 F150 with E40D and 4.9 six. Tranny was fully rebuilt about 10k miles ago. Never have seen a light on the OD button on the shift **** and didn't know there was supposed to be 1.

Now for the question. Since the rebuild, the transmission is smooth and shifts very nicely MOST of the time. The only problem I have is that very intermittently, especially when towing the boat, the upshifting will be hard enough to almost slam your head into the headrest. Also noisy and sounds like you just did a power shift of the Drag Strip and dumped the clutch. No codes show up on the reader. Since this truck only gets used to take the boat to the lake and back, it is low mileage and little use but differential and rear wheels get a LOT of water dunking. Hasn't done this for my mechanic. Anyone have any ideas about what might be causing this? Just don't want to destroy the tranny rebuild for an intermittent sensor or something else simple.

 

Read the codes. Without the codes, all anyone can do is guess.

 

I have hooked up 2 different code readers and get no codes for sensors or transmission. Has stumped my mechanic, the tranny rebuild shop, and me since it is not showing any codes. So, any guesses?

 

Interesting. Have you checked your fluid?