vibration during accel and decel

[XWrench3]

my jeep has developed vibrations that ALMOST mimics a bad front u joint (rear axle) vibration, meaning that I feel it thru the seat. I rebuilt the front driveshaft not very long ago, but just to be sure i tried to make it move also. which it is tight. it happens mostly during accelerating and decelerating, but there is a certain amount at speed as well. I put it up on the ramps, and with my daughters help got it situated so I could SAFELY crawl under it with no load on the drive train. there is no play in either drive shaft. my floor jack is out of commission so I can not jack the vehicle up and put it on 4 jack stands and put it in drive, I was thinking it might be the torque converter bolts coming loose. but I do not see a way to check them, without removing the transmission. which is beyond my capabilities now, because of getting to old to do that heavy of work. I did have a thought, is it possible to get to the torque converter bolts if I remove the starter motor? the only other thing I can tink of is if something in the transfer case is going bad. and that also falls outside of the scope of my ability.