My 2002 Jeep grand Cherokee will not shift out of 2nd went to auto zone they ran the computer on it it said the ECM we replaced it its still not fixed. When it acts like it wants to go into 3rd it jumps then I lose everything it stays in 1st gear and just revs I can manually put it in 2nd and 3rd. Help please!! We also replaced the speed sensor

 

3rd and 4th gear are controlled by governor pressure and speed sensors. I would suspect a governor pressure sensor switch. AND it's probably not the computer! Those guys say they don't work on commission, but I sometimes wonder. They certainly like to sell the high priced parts!

 

Changing out those solenoids and the governor pressure regulator is a pretty simple and straightforward job

 

Hopefully the Governor pressure sensor will help! My jeep is a grand Cherokee limited 4.7L V8 I've only had it for 2 week's. I'm ready to have it running smoothly again!