Re: 690 miles from home haveing issues!!
Your jeep has the 5-45 rfe transmission, which uses 3rd gear for limp home. But it will only go into limp mode when the TCM sees a situation which could harm the transmission. If a TPS would totally fail ( no output signal anymore, from which i never have heard of), the engine will not pass idle rpm.
Oh, and regarding the drivetrain noise, its most probably differential gear whine.