It is engaging sometimes and not others and the challenge is finding the pattern, which I haven't. Sometimes it will seem to slip at higher rpms and others it will slip until you hit higher rpms. I have adjusted the cable on the throttle body and have checked my fluids and have replaced my TPS and speed sensor (HESCO enhancement kit). The transmission was rumored to have about 115 k on it when I got it from the salvage yard and I have put an additional 50 k on it since. Sometimes it will not shift from first and seems to jump to third at about 40 mph. Very confusing, I wanted to buy a used TCU to just test the theory as they are going for about 75 bucks around VA junk yards, but no exact 88 models just 89 and 90's. (When I type slip, I mean that you give the jeep gas and you get no acceleration, to match the rpm's which are functioning just fine with no engine lag.) Worst case I am ready to buy my way out of this, as it is making me crazy, but my skinny wallet makes me work for it to be fixed by my hand if it can be.