my trk continusoly d0wn shifts between 45-60 mph up-down-up down on flat ground

What is your question?

BUT WHEN PULLING A GRADE ABOVE 6o mph runs just fine! I just had a dodge mec. and he adjusted the front band on trans. and the problem went away! FOR 1 WEEK ! then came back! I also replaced the driver side sensor on tranie. and I very rarely tow anything!