i have a 2004 grand Cherokee limited. i went wheeling with some friends today, and we noticed that when im in 4all time. that my front wheels dont work but in 4 Lo everything works fine. is this normal?
It sounds like the clutchpack or however it is the 247 works to limit slip is worn out. When that happens, it remains in 2wd all the time. 4w-low in the 247 reverts to the old true lock like the 242 and second gen 249's had. It bypasses the limited slip stuff. I don't know all the ins and outs of it, just the basics.
The 247 transfer case (Quadradrive) uses a gerotor pump that senses speed difference, not torque, between the front and rear axles. In 4alltime the rear wheels get all the power until they spin faster than the front, and then power is progressively transfered to the front. 4Lo locks both axles together at a 2.72 reduction gear. Unless you were spinning your back wheels, the front won't have any power.