Let me apologize for this question up front because I know nothing about the torque converter, what it does, and how it is suppose to work, etc. Anyway, my truck sometimes downshifts hard, especially after going down a steep hill at about 20 MPH where I live and climbing an even steeper hill. I can actually hear and feel the down shifts. At times when I stop on a flat surface, it seems my truck wants to keep going and there's hard downshift and thumbing sound. Of late, my truck started bucking when I come to a stop shortly after I first start driving the truck before the engine gets hot and it's hesitating when cold at low speeds. It will also cut off abruptly when I place the truck in reverse. It will not move, just cuts off in reverse when cold without giving the truck any gas at all. You absolutely cannot back it up. Now after my truck warms up after driving it above 40 MPH for a few miles, it starts to smooth out and the hesitation is gone. However, I still have to be careful backing up even when warm. It still acts as if it's idling too fast to back up. I told my dealer about the problem and he seems to think there's a problem with the torque converter. Could this be the case? Any suggestions on what the problem might be? At first I thought it was electrical, but can't understand why that would affect backing my truck and shifting it

 

man that sounds like a LOT of symptoms. my guess it is more than a torque converter. the torque converter went out on my '94 F150. the symptom was a low speed shudder under acceleration; sort of like driving on light washboard.

 

Go figure...I got in my truck today and it runs great, as good as before with no surging, bucking, nothing...just smooth running and shifting even when cold.

I am scheduled for a power transmission flush this week since I hadn't done anything with the transmission after 73K miles...it's about time.