Originally Posted by dcorn
Seems like normal gear mesh noise to me. Every Jeep transfer case I've heard in 4 Lo has a whine to it as well, and that's chain driven. A gear driven transfer case is going to make some noise, especially at high rpm's.
You've heard the OP's transmission then I assume? If not I don't see how it seems normal if you can't hear it. So many people are convinced it is the normal whine without ever hearing the possible noise in the first place.