03 Sierra 8.1 dual batteries

[Mike Karder]

I recently bought my truck, it's a 2003 4x4 with the 8.1, my dad and my boss both owned one of these before I bought this one and neither of theirs had dual batteries and mine does, I can't seem to find a RPO code on my glove box that says there was a dual battery from the factory but the wiring is definitely factory original in the fashion of a TP2 RPO, the problem I'm having is the auxiliary battery went bad and started leaking acid, I had to just take it out because I currently don't have another option. My question is, do I need that battery? Will it hurt my truck to not have it? Do I need it to tow? I just can't seem to find any hard information on the subject besides guys trying to install or maintain this system for snow plowing purposes.