96 trooper few problems/questions

i have a 96 4wd trooper automatic, i was told that i need new axles soon so that may be the problem, anyway... lately i have been driving and when i go over a bump for the next couple hundred yards i can hear what sounds like im dragging a tin can and then there is a pop like i ran over a rock and it hit my undercarriage, there is either silence after ward or it repeats after a little bit.

also when i am decelerating from about 20mph down there is a hesitation/idk how to describe it, but it feels like the trans is going into 2nd gear really hard for those of you who have had trans problems, its a slight jerk like that but backwards bc im decelerating.

i just had my rear diff cleaned out or whatever at the local express lube and its still doing both problems.

and also when i get up to 50mph the pedal and the rest of the car start to vibrate when i exceed 55mph its not noticable anymore. its only around 45mph to about 53mph and i can feel it the most in the pedal.

can anyone help me out? thanks a lot.