I just bought a 96 ford F350 with the 7.3 and automatic with overdrive.

Around 50 RPM and up, when I let off the gas a little, Rpm goes up 200-300 Rpm. Give it some gas and it drops down. This happens constantly. Seems like the torque convertor is locking and unlocking ???

Please give me some Ideas , how I may Identify what problem is. I have checked the fluid.

This is my first post.

Thanks