Why will it not set in park and 4wd not working
Any incline it rolls and front wheels have no power
Repair guides and support for the first generation Grand Cherokee ZJ, an upscale mid-size SUV built by Chrysler's Jeep division.
Zane Murray , Sounds like a problem with front drive shaft or axles/CV joints are bad/broken which would allow Jeep to roll and cause engagement issue to front wheels. Have a good mechanic check front shaft/ axles for fault. A worn or out of adjustment parking Pawl (inside transmission)will also allow vehicle to roll when in park. The Pawl is inside the transmission and can be adjusted fairly easily if determined to be the issue by a good technician. Attached a couple links below, 1st link is a cherokee forum that discusses the shaft/axle issue and the 2nd link talks about the parking pawl. Good luck.
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I have a 98, I'm still learning how things are setup on it. What it sounds like is that the transfer case is in neutral. Which would cause no drive to any wheel. Try this, start it up, put trans in N. Then move transfer case lever all the way forward to 2wD. Now see if it will move.
Let me know everything that you have done or tried along with what it's doing and when.