sorry to hear about your troubles. most young tech's have lost the art of trouble shooting. From my own experience here is what I would check, The tranny mount Check to see if bolts are tight or if it is broken. Transmission cooler lines to see if they are not rubbing and last check to see if any of the heat shields are not rubbing. Then also check U-joints, slip joints, center carrier brg. One last thing, one day was driving on a trail slow 2 mph and we fell into a rut . With this we came to a complete stop. because of this the motor mounts broke, they are designed that way to break on a hard inpact.

 

Grap the drive shaft and shake side to side checking the u-joints. I have 3 from my trans to the rear differential. The middle u-joit was shot to HECK. I replaced them all. I have 43000 on the clock and finally went out. Just something to check out.