Driveshaft problem

I Have an 93 ex cab b2200 when I slam down the back my driveshaft makes a grinding sound . should I buy a one piece driveshaft or is there something I could do to fix it ?

You have to check and see if the driveshaft is rubbing on the back of the cab or the gas tank crossbar possibly. I'm sure others can have other ideas as well.

what kind of rear suspension setup are you using?

i got a fwd 4 link with the bags behind the axle

sounds like its rubbing cross member, the cab or the pinion might be shifting...