Automatic Transfer Case Fluid

I have a 2000 Siverado 2500 with 6 liter and Auto 4WD. Transfer case made
screeching sound on startup, much like a loose belt. Turns out transfer case was low on fluid, dealer said it didn't look like a leak. Topped off with fluid and now 2 months later, the screech is back. I just checked and it's low again. I can see that the vent hose is wet and a cross member is slick so I assume it's blowing out through there, why, I don't know. All dealers in my area are now closed and I have to put in some kind of fluid other than the GM recommended part number. Any suggestions?? Whatever I put in for the weekend can be flushed and changed on Monday.

Personally I wouldn't use anything else in your transfer case other than the blue goo from the dealer. I have the same truck. When I got it, I thought the tranfer case was fried. It made all sorts of horrible noises and vibrations. It turned out the fluid was just old and burnt and after it was replaced most of the noise went away. I still think some damage was done since it's still not as smooth as most of the others I've driven. The stock fluid is some kind of synthetic with a friction modifier for the clutches, anything else might cause major problems.
BTW it's nice to not be the only one on the board with an autotrac 2500.

I wouldn't put anything esle in your transfer case.....I had the same problem, and tryed several differnt types of fluids.........all they did was just make the transfer case bang like crazy......then I saw the tsb about the new transfer case fluid (auto-trac 2), changed it, and now she runs like a champ..........

Yup, only use the blue GM autotrac fluid to avoild further costly complications down the road