James4runner

the truck is a 1994 4runner V6 3.0 5 speed manual.I just bought this truck it has 240K. I put my truck in 4 h, I started to take off and I heard a loud clunking noise while it's in motion. i drove a little further and the noise just got faster with increased speed. its a loud clunk noise, it was worse when coming down a hill in first gear (load). i tried in 4 low just for kicks and the clunk was worse. doesn't make any noise in 2wheel. the noise becomes worse when i turn the wheel. however, the truck drives normal on 2wd. please assist.