I've got a 95 f150 4×4 with a 351. The transmission works great in reverse and will pull then slip and then pull again etc. I've replaced the filter and fluids. Anything else it could be.

 

Drive in Low, Second, etc. See what happens.

Richard

 

UR going to have to get it to the repair shop for a rebo, the valve is malfing causing damage to the clutches. If U want to try replacing the modulator valve it is pot on the side. It may be leaking. A trans tech can help U decide how to save money. To continue will mean destruction.

 

You can not say a valve is malfunctioning without more diagnosis. That is why you check the behavior of each gear manually. See what should be engaged for each one, then you can narrow down your problem. A blow seal and a variety of other causes can do the same thing.

Richard