1996 Ford Ranger Question: my 96 ranger jumps to the side when i hit a bump in the road

driving down the road if i hit a bump or a pot hole the rear end of the truck seems to jump to the right.enough to where i have to turn the wheel. i jack the truck up and check for loose parts and found a little play in the left rear axel and a worn lower ball joint on the right front. my question is after i change the ball joints if the problem is still there where should i look next