Could be the installation of the tranny.The u-joints didn't go bad while the driveshaft was out of the truck unless the caps came off and were not replaced correctly with all the needle bearings.

 

well one of these days during this week i am going to replace the one u joint that has a little play in it and see where i stand after that....

 

while you have the driveshaft out, you might want to crank it and run it gently. see if the vibration comes out of the transmission/t-case, or if its smooth.

 

i didnt think of doing that....but i think i will.

 

when i am at highway speedss ( or any) and im on the throttle thats when it vibrates....but if i slip it into neutral even at the same speed and rev on it.....nothing...its smooth...only does it vibrate when there is torque on driveline

 

It's not the u-joints or driveshaft if that is the case.

 

any ideas then???

 

Any noise associated with the vibration

 

nope no nois at all.....the only noise i get is from my 4 wheel drive lever vibrating around

 

I am having the same problem with my 98. Did you find out what was causing the problem? I put on new wheels and tires and new u-joints and it still vibrates same as yours. I have a man trans.