What would make my jeep cherokee down shift when it doesnt need to?

My 2000 jeep cherokee down shifts from overdrive to third gear even on flat ground. And then it will kick in and out of overdrive rapidly going up hills.|||sounds like the TCL(torque converter lock)solenoid, and might also have other issues.Is the check engine light on, for if so it might have trans codes that need scanned and attention needed to those codes|||with similar problems I replaced the governor pressure transducer and transmission solenoid and fixed it .