Having some trouble with my '91 F150 4x4 5.0 EFI. I think it has an E40D, it is an auto with push button OD on dash panel. I've searched past posts but still not sure. Mine sometimes delays going into gear when put into drive or reverse. Sometimes even slips or revs without moving when gas pedal is pushed, mostly at idle but has happened even at hwy speed. At idle, when it delays, it hits really hard when it engages. Once the speedo went crazy at hwy speed while slipping, going from about 20-60 back and forth. Checked fliud level and was about a quart over, but actually seemed to work better before I drained it down.(just bought used, no history) Have not cked codes. Any help??? Also forgot to say, has a 6" lift so driveshaft angle is sharp, if that matters. Thanks!

 

I would have the tranny checked and even flushed out and give her some new fluid.

My 2 cents.
Good Luck.

 

Do a complete tranny flush, all 13 qts. and deffinetly change the filter.

 

if i remember correctly theres a sensor that will do that