Re: 98 Jeep Cherokee That Won't Upshift, Help!
98's have a digital speedometer. Try doing the "key dance" by switch the ignition from Off-On, Off-On, Off-On and leave it on "On" the third time (Three times quickly) and see if any codes pull up!
Since you have a 42RE it might be the Governor Pressure Solenoid Valve. That's one of the main problems with these ZJ's from 93-98 on the 42RE Tranny's