84 V6 automatic with OD ... while driving I appear to get a severe Hesitation in Drive power which appears at about the same rpm every time ... predomenantly this is occurring in Overdrive around 50 MPH ... the engine with no load at that rpm doesn't appear to have any hesitation so I am expecting this has something to do with the Transmission. I can get this to happen regardless of which gear the car is in. Is there a simple test that can be done to definitively point a finger at the Tranny? The thing that bothers me is that the Tranny appears to work fine above and below this rpm. Almost as though this issue is occuring when the Tranny is switching Gears

 

Have you consisdered misfire under load?