I have a 2003 WJ 4.0L auto w/OD 242np Tc 85,0000miles
here is the problem out of the blue it started shifting funny it wont shift until you hit 4to5 thousand rpm it shifts into drive ,reverse fine and when manually shift goes into low but doesn't want to go into second manually. for the record its got brand new fluid and filter makes no odd noises just wont shift right. Shes been taken well care of this stumps me any help would be greatly appreciated

 

When you changed the filter, did you notice weither the throttle cable was connected to the valve body? It's possible it's disconnected.

 

Like mentioned above, check the T/V (throttle valve) cable. It runs from the throttle body down to the trans. This cable mounts up to the trans beside the shift cable. There should also be a return spring down there that keeps the linkage pulled forward with no throttle input.

Looking at the linkage on the trans, you might have a buddy cycle the throttle open/closed so you can see if the cable and linkage is moving back and forth. You complaint sounds like either the cable is way out of adjustment (too tight), cable is binding, or the return spring is off or broken not allowing the T/V linkage to return backward.