Universal joint bad in driveshaft at rear end. You can replace these with a little effort. You must remove driveshaft from truck and carefully press the staked universl joint out. Clean and deburr driveshaft yokes and carefully install universal joint, Precision 812 from Napa or 11001 Neapco from Advance Auto. Once you have installed and centered universal joint, spot weld to keep caps from coming back out.