Truck Repair: Ford Ranger 4x4, 4WD low range problem, universal joints, ford ranger

Question
I have a 1999 Ford Ranger, V6, 4x4 with 74,000 miles on it. Seems when the truck is in 4WD, low range only, and I go to back up a steep hill (my drive way) it makes a wicked noice and feels like it is popping in and out of gear. It does not do this in 4 wheel Hi range or 2 WD.  I've had the drive shafts and universal joints inspected and the front brakes changed.  Could the transfer case chain be the culprit (slipping under the hi torque of the 4 low range or what.) And how costly a fix?

Answer
Hi Jim,
I'm not sure where the chain comes in to play in reguards to the hi/low range. I think the chain does both ranges.
But in the transfer case is where I would expect the problem to be.

If you want to check a manual, it would be worth a trip to the public library, to the refference section. They have factory and aftermarket manuals on about everything.

Van