How about the dust shield of the rear (or front) flange? It could be bent and contacting the transfer case housing.
BigMike-
Have you ever seen a stock Toyota U-joint (Koyo) with 2 grease zerks? The CV that the shop welded on my driveshaft has Koyo joints, but there are 2 grease zerks on each joint (so a total of 4 u-joint zerks + 1 CV ball zerk on the CV unit. I'm wondering if someone cobbled together parts for ujoints or if this is an OE design. I have a hunch the squeak is a ujoint, despite what the driveshaft shop says.