Hi there, I have had similar problems in my 94 Grand Cherokee with the 4.0L and 42RE transmission. What type of transmission do you have? A faulty sensor or solenoid in the transmission, such as the governor pressure sensor or governor pressure solenoid, may be causing the transmission to not shift into OD. You can check if there are any trouble codes stored in the control module by cycling the ignition on and off three times, ending in the on position the third time, then counting the number of times the OD light flashes. If the OD light flashes 2 times, pauses, then flashes one more time, a trouble code 21 (Governor Pressure Solenoid) is indicated. If the light flashes 2 times, pauses, then flashes 6 more times, a code 26 (Governor Pressure Sensor Offset Drift) is indicated. There may be other codes that can be obtained by counting the number of times the OD light flashes. There may also be mechanical damage inside the transmission. Was there any metal or friction material in the pan when you changed the fluid?
Hope this was able to help. Good luck with your Jeep.