Rear Problem

Ok here is the scoop. My pap has a 1989 C1500 8foot box 5.7l v8.
When he comes to a stop and is at full stop brakes on then goes to move forward very large clunking like sound comes from there. He had it at the garage but they said his rear brakes had dirt in them and said it was fixed / It started doing it again the day he came home from there. Its a hard noise to describe but i thought maybe suspension bottoming out because he hauls appliances and drives w a load on . Any ideas let me know

easiest would be to take it to another shop and get them to diagnose it. probably too much play somewhere in the driveline such as u-joints, steady bearing, excessive play at driveshaft slipjoint or might be something in the diff such as worn pinion bearings, excessive gear backlash, worn case gears/case/pin or chewed up axle splines/inner side gear wear. also check for weak/broken springs, sometimes they can slap together when the axle wraps up. good luck

ok will let him know would have gotten back to yous sooner but net didnt work last night

check the bolts that hold the brake backing plate to the rearend to see if there loose. mine were loose on my 87 an dmade a loud clunck when i pulled fowards right after backing up, or stoped real quick.

he took it back to the mech today cuz the mech said on the phone it looked to him that the front rotors were shot and making the noise. personally i dont like the guy cuz he does crappy work but the labor is cheap. so ill let u guys know either tomm or friday whenever my pap gets it back

He got it back from the shop today installed new front rotors and no noise. It seemed to have fixed the problem but the next thing he said will be brake pads for the front but other than that he said that nightmare is over. Thanks guys for the knowledge and assistance