I have a 1997 Ram with the 5.9 V8. When I am stopped and it drive I hear a clunking sound, but I put it in neutral or park and it goes away. When I am driving somtimes it will jump up 100 to 200 RPM's. It is like the torque converter is coming unlocked. It does it mostly above 40 MPH. Any help on what it could be would be appreciated. I did replace the TPS but that did nothing.

Brian

 

sounds like the flex plate is hitting....that would be the first place id check out...because if it is hitting, DONT drive it.

 

my truck is doing the same thing just started lately. mine seems like it slips in overdrive to me but im not a transmission guy.