i have an 88 jeep Cherokee with the 4.0 straight 6, and when i drive the transmission shifts perfect but when i am around 40mph or so i step on the gas a little more it shifts into OD and then i will let off just a little bit and it goes back down a gear but it seems like it is super sensitive, keep in mind that this is my first jeep ever, i am a German car enthusiast by nature, so let me know your opinions or concerns.

 

Try adjusting your kickdown cable. It's connected right next to the accelerator cable. Push the half circle shaped release button in and push the plastic end piece (where the cable comes out) all the way back in to the body of the adjuster. Release the button, then grab the lever on the throttle body and twist it to wide open position. (with engine OFF of course) You will hear a slight ratcheting sound as the cable slides thru the adjuster. That should do it. Test drive it. If it shifts normally, yaaay.. if not, don't drive it very much as if it's too far off it can cause transmission damage. If you need to re-adjust it, repeat the process but this time use the gas pedal to attain wide open throttle instead of the linkage on the throttle body. It could be some other issue, but this is a quick/easy/cheap possible remedy