I have a 1997 F150 with the 4.6L. I have noticed that around 40 mph the trans gets real jumpy and it also does it around 70 mph. As soon as a certain mph is reached though, it goes away. Say maybe 2-3 mph higher. What causes this and should I be worried?

The truck has 114K miles on it. I have owned it for 3 years.

 

tranny gets jumpy? are you sure it is the tranny, not the engine?

 

I've had a similar issue. It's a large clunk as if the transmission starts to shift then doesn't. Feels like you pull it into neutral then back into drive quickly. Tends to happen only in hot weather after you drive for a while. If you can figure it out , let me know. I've been working on it for a year. ALthough, for a while I suspected an ignition problem I am now back on the transmission.

 

i heard somewhere that it might be a sensor. like a TR something sensor that can go bad.