I have a 2001 ford F150 4.2 automatic. It shifts through all the gears well. The torq locks and unlocks well. on larger hills when the torq unlocks it does just fine, but when the truck needs to shift out of over drive completely it seems to rev high then go into the next lower gear and go on. This happens rather I use the button to take it out of over drive, or if I press the gas pedal down more to disengage over drive. I have looked around and am wondering if someone has had this issue ad could maybe tell me where to look first if I drop the pan. There is no slipping when driving, just revs high before the next lower gear engages then goes on when on steep inclines. About 155 on the clock. No codes are thrown on the computer and the only light is on is the ABS light. The codes are from the front two sensors. I have a long trip soon so I wanted to see if I could take care of the issue before we take off I a few weeks.

Any assistance would be appreciated. Thanks.