k's95

i just bought my 95 jeep cherokee and it has a kick to it when i stop and when i go some times. i have even have it jerk a little bit when it shifts. it almost feels like the trasmision is moving when i stop. i talked to my friend and he said it has backlash in the rear end an i need to put shims in it can anybody help me out with this. What do i need to do and how much is it going to cost me to fix it.