I have a 96 XJ with a stock 6 4.0HO, basic 3.5 lift on 31s, as far as i know everything else is stock. So heres my issue, over 40, when it shifts into 4th, if the RPMS are over 4200 it will hold power but as soon as i go under 4200, it drops and i lose power, the engine diesnt rev and when i push the gas more it shakes. If i push the brake pedal a tiny bit while its shaking it will(i think) downshift into 3rd? It either downshifts or allows the gear to work. Ive posted all over facebook and asked evryone i know and nobody seems to know what could cause it.

Transmission fluid looks a lil purple and is in the middle of the lines and smells normal, no metal in it. This is my daily driver so i really need to get it working right.

Anything i forgot to put that i need to i can edit and include, thank you for your time.

 

Your symptoms possibly describe some fault in the torque convertor ?.

If you measure the white & black wire on the 7 pin rectangular connector that goes down near the trans fluid tube, it should read about 11-14 ohms

that is the TC solenoid, resistance is between ground and each solenoid terminal

 

My Cherokee used to have an intermittent issue where overdrive wouldn't work, sometimes it did and sometimes it didn't. I have the AW4 trans. Do you know what trans you have? The problem on mine was the transmission range sensor. I'd guess based on the name it tells the computer the engine rpms and vehicle speed to determine what gear it should be in. This part is a two in one part, it is also the park neutral safety switch, which tells the vehicle what gear it's in and will only start the engine in Park or neutral. When my sensor was defective the Jeep wouldn't start in neutral. I replace this and it started in neutral and I haven't had an overdrive issue since. I would try starting in neutral and see if it will or not.

 

Ive replaced the throttle position sensor and crank position and neutral safety, none have fixed it, ill test the torque convertor reply tomorrow and see what comes up