I bought the truck yesterday its got 88000 on the motor and 203000 on the body. When I put it in reverse it hesitates to move and when I put it in drive I hear a loud clunk. But from first gear on up its smooth shifting and no problems. What could this be? It just had a motor put in it so maybe they didnt hook something up right or something.
Bit hard to diagnose this with out actually feeling the problem, so with that said, start with transmission oil, is it clean and full? Check drive line for loose or worn components and also see if you can check torque converter bolts and flex plate for cracks.