My wife and I have just purchased our 2nd Durango! We just got a 02 RT with 84000 miles on it, it is cherry. I have notice when ou cruise control is on about 70 mph (or really any speed)upon climbing a hill my rpm increases about 200 and feels like the tranny is slipping. If you take it off cruise and hold it steady it will never do that unless you turn the cruise back on. I have notice no other issues with the tranny at all, it shifts fine and the fluid seems to be in good condition and at the right level. Anyone have any suggestions?

 

It may be the TPS.

 

TPS sounds like the problem. Might as well fully clean and inspect the whole Throttle Body while you are there.