Not sure what type of transfer case how do i find out? and here's another puzzling question...Just for kicks i put my truck in 4hi went into reverse tried to turn the wheel in either direction and it felt like the front end locked up and that the back was pulling the vehicle rather than all 4. But when i take it out of 4hi and return to normal mode it works correctly i can go in reverse and turn no problem.....HELP

 

When you say normal mode do you mean 2wd or AWD? The reason I ask about the transfer case is to see if the vibrations only occur in 4wd, or if they still happen in 2wd as well. You mentioned they only happen when you accelerate which makes me wonder.

 

seems to only happen in 2wd and only when i accelerate. If i put in 4wd going in drive seems normal but put it in 4wd and in reverse the front end locks up.

 

Crawl under the truck and look at the back of the T-case. 3/4 the way up is a round seal, and on this seal is the model.

Your T-case sounds normal the way you describe it.

When you lock it in 4WD and reverse the rear wheels are locked to the front wheels. The rear wheels are turning different revolutions then the front when you are turning. This happens in both forward and reverse operations.

Again, check the insides of the rims for mud.