Re: Transfer case question: Manual vs Automatic
 

If you have a big round AUTO button at the top of the 4x4 control buttons it's an Autotrak transfer case. That's the one that takes the blue GM Smurf Blood.

Floor Stick and three button electric shift "2, 4H, & 4L" only are manual cases. The GMT800 chassis trucks with these cases used Dexron III... AC Delco 10-4033 / GM 88861900.

Re: Transfer case question: Manual vs Automatic
 

Wasn’t the auto t-case (that drinks the smurf blood) only available in 1/2 tons?
As hatzie helped me get my arms around, since Dex III is no longer produced and certified, DEX VI is the authorized auto trans fluid and Man Trans and T-case fluid 88861800 is recommended in the TSB for the t-case.

Re: Transfer case question: Manual vs Automatic
 

I believe they were available in the 3/4 ton SUVs too.
Probably not on the 3/4 ton pickups tho.