New to the forum.
I've been looking into this issue for the past few months without success. Heres the problem. I have a 1996 f150 with a 4r70w auto trans and it has started to act up. At first it would slam into its gears. I'd actually let off the gas between gears so it wouldn't slam.
But now it's gotten worse, at 15mph the trans will shift all the way into O.D. then lug. If I come to almost a complete stop then it will shift back down. If I try to shift manually into 2nd or 1st then the truck stalls out.
I changed the diff speed sensor after a friend had the same problem, I've also swapped out all the fluids, checked all wires and connections and everything is good. Any help would be greatly appreciated.
1996 f150
Engine:302
Trans:4r70w

 

Attempting to diagnose over the net is not always good..
I would suspect there is a problem within the valve body of the trans. The only way to confirm this is to have a good trans shop check it out .
Sometime we don't get much "wiggle room" and looking for a quick fix can be misleading and expensive.

 

Welcome to the site..

Any OD light flash, CEL?

 

Nope nothing at all, no check engine light, the o.d light turns on and off as usual. When I scan it, there no codes. Shifts from park are smooth no jolting either.