I went through the same thing a few weeks ago. Went to my dealers parts counter and asked for 2 qts. transfer case fluid, Parts guy comes back with Mercon V fluid. So i tell the parts guy that i need transfer case fluid not Mercon V fluid. The parts guy says Mercon V is the correct fluid. Just then the tech that did my studs last month walks up, So i ask him if the Mercon V is correct, He said I'll check he comes back with a notebook computer looks it up on fords network and guess what, The correct fluid is transfer case fluid. I'm Not sure whats the difference in the fluids.

The parts guy didn't know ford had labeled transfer case fluid.