Most likely it's Dextron III automatic Transmission Fluid. Might want to check the Amsoil site - they might have a look-up.
It is next to the transfer case solonoid located underneath the damp control spectrometer.
1999 Chevy Tahoe automatic transfer case requires 2.2 qts
The transfer case fluid on a 1985 Chevy Suburban should come to the bottom of the filler hose. It must be on a level surface to accurate measure fluid levels.
2.5 QTS.
Full it until it starts drizzling out of the fill hole on the transfer case.
Dexron. Automatic Transmission fluid
get the seals checked out around the transfer case and tranny
NO. If you keep finding yourself ADDING transmission fluid often and you have no leaks but the transfer case is over full then you need to remove the transfer case and replace the seal in the transfer case where it bolts to the rear of the transmission.
That year requires--------DEXTRON VI fluid.
Dextron II
The fill plug is on the left side of the transfer case. You remove the fill plug, and the fluid should come to the bottom of the fill plug.
It holds 4 quarts>