I have a 1994 Jeep Grand Cherokee that had a bad transmission. Its a 4wd, 4.0 liter, automatic, 42RE. Swapped in a trans from a 95, "supposed" to be good. It runs great in every position except reverse. Tried swapping P/N/R switch. Tried unplugging solenoid case connector. Just gave it tune up; plugs, cap, rotor, air filter. Has new filter and fluid in trans. When put in reverse, it runs like crap and dies. If I give it enough gas I can keep it running and it moves in reverse, but still runs bad. In drive it idles and runs great and it will even downshift fine. Does the same with previous PCM and the current one. Would changing the valvebody do any good or should I go hunting for another transmission?