Great tip! Not sure if his model will be equipped with that switch. That switch was known as the vampire. Suck the fluid right out of the transfer case.

 

I'm a bit late with checking the OEM Manual. Correct about the hose.

This should be the vent to atmosphere of the "TRANSFER-CASE" vacuum switch.
Normally it is just the hose which has a clamp and a sponge cover. It is used as a vent.

There should definitively be no fluid coming out of there.

To make sure we do not mix up things here.

From front to back we have: ENGINE - TRANSMISSION - TRANSFER CASE

The transfer case is bolted together with the transmission and as previously stated a leaking seal could dump TRANSMISSION FLUID into the TRANSFER CASE.

The fluid for the TRANSFER CASE is also automatic transmission fluid.
Service manual says DEXRON IIE.

 

Is not the fluid a special kind if you have a "4-button" transfer case?

 

More recent blazes could be. The 94 is the last 1st gen. Electrically actuated Blazers have only one switch with two positions.

Manual says DEX IIE for the transfer case and DEX IIE or IIIE for the transmission on these Blazers.