My 2000 3500 5.9 TD engine has begun to surge between 1100 and 1400 RPM after it shiftsinto OD at about 40 MPH or so. After the shift the surge moves up and down from 1100 to the 1400 RPM range and will not quit until I can increase speed.

This has never been an issue and have always driven with the "over drive on"I am a few miles south of 100,000 miles and I have been careful with maintance.

Any ideas what might cause this condition? Thank You

 

this comes up about every other month or so. . .what is going on is your haveing an electrical disturbance either in the trans wireing harness, or the main ground. this is causeing the torque converter to lock and unlock giving you this surge.

first thing to do would be to follow the wireing harness and make sure the wires are loomed properly and are not rubbing on each other. then check the main battery ground and ensure you have good connectors and no corrosion