The main problem with a loose upper arm/joint will be slightly uneven tire wear. There is also the possibility of some clunking noise. Unless the part is so loose as to be ready to fall apart, there is no safety concern, or immediate need to get it fixed. I'd have one or two more shops look at...
I've tried a few over the years: Lowrance iFinder H2o, Garmin Geko 101, Garmin eTrex Summit, Garmin eTrex Vista CX, and my latest and greatest: Garmin Colorado 300.
The Colorado 300 will also do street navigation if you add city navigator maps. The system and menus are different from the eTrex...
We've seen a few Crankshaft Position Sensors fail on Jeeps. It's located on the driver's upper side of the transmission bell housing. With a long pry bar, lightly tap the sensor while an assistant tries cranking the engine. This sometimes will result in success, and confirm the fault. Also, if...