Re: 03 limited stuck in rwd?
Indeed good to check if the front drive shaft is in. But quadra drive uses the NV247 T-case and that one is known to give problems with the progressive coupler inside the T-case. (also used on quadra tracII). I never red anything about why it happens, but to me the problem is the difference in tire wear front to back. If the front and rear wheels are not swapped on regulary basis, there will be a (small) difference in tire diameter due to the difference in tire wear, and this difference in diameter will actuate the progressive coupler all the time. The pressure will be low (since it depends on the speed difference between front and rear propeller shafts), but there will be a constant force applied on the coupler clutch plates, which causes them to wear. The coupler is a very expensive part and you better look for a good junk yard part, or, as many other already did, swap a NV 242 in its place.
In above case the 4Lo should still work, since it bypasses the progressive coupler. If 4Lo also doesn´t work, then there most probably is a problem with the chain inside the T-case.