Transmission fluid question

[takeiteasy04]

Hey guys,

I have a 1997 C1500 with a 4.3 V6 and an automatic transmission. It has a transmission fluid leak, and I need to keep it topped off until I can get it serviced. Do you folks know the proper fluid to use? I have the manual that came with the truck, and it says to only use DEX III. However, the associate at AutoZone (and some other internet sources), claim I should be using DEX VI.

Any and all help is greatly appreciated.

Thanks in advance!