I went with AGMs when my batteries failed two years ago on my 2009 Duramax
On one truck I had (2006 Chevy D/A) I had another issue after replacing the batteries with Costco wet cell batteries. The water drains down the cowl cover, under the hood and right on top of the battery, and leaked in to the battery caps on the wet cell, overfilled in, and puke acid on the battery tray, creating a mess. So, on the GMT800 "Chevy" trucks, I'd highly recommend AGMs.
I don't know if the same situation occurs on the GMC version of the GMT800.
