??? help

[stanley TILTON]

I really can only explain it and hope someone reads this and they know. Its something it appears i only notice. 3 shops and endless people loooking at it. It started as small vibration only on interstate felt in pass. rear side. Now it will drive like its a tank every road different truck riding. concrete roads being the worse. It feels like its vibrating apart but then it will stop and feel  like a new truck drives smooth for a wile then back to crap. replaced motor mounts,hubs,back shocks , universal joints still the same. any suggestions. If others drive it they dont, You have to drive long period and you will notice two different trucks driving. At 40 to 45 holding steady the rpms bounce up and down about 300 rpm . Makes driving in town tough. 

[diyer2]

Torque converter?

[bubbanbrenda]

I agree if the rpm’s are jumping up and down it’s probably going to be transmission related.

[dna9656]

I didn't consider the torque (T/C) converter; I was thinking maybe a rear bearing or a de laminating tire. I think you should get the tires looked at anyway just to rule them out. On further thought, I think the T/C was a pretty savvy call. Unfortunately to check it is going to be a PITA big time, especially if it turns out that it ISN'T the T/C. I suppose a real (professional) trans shop will have a way to diagnose the T/C without removing it to trouble shoot it; but then again that may be the only way, I donno.

I would ask around and find out who the best transmission shop around is and go there. Don't forget to check out the BBB site for complaints and believe what you read there. Most folks are not vindictive without reason.