In Feburary 2018 I bought a 2003 Ram 2500 built in January 2003. It still had the original Diamler-Chrysler batteries in it. They were rebranded Delco/Delphis with the Green dot window in them. Worked, just barely. I immediately searched and found AGM batteries that were on sale, in this case it was Pep Boys Bosch AGM’s 25% off. Somebody is always running them on sale, last time, it was Sears when I needed a battery for the Motorhome (sold) and their AGM’s were on sale, 25% off.
I used to be picky, nothing but Delco/Delphis, but after years of them, I started encountering early failures, so I now shop on price. Pep Boys has alot of parts including batteries for 25% off. AGM battery for yours would be $146. Just shop around.
DEF fluid will freeze or get slushy, the tanks in most vehicles have heaters because of this. Failure of the heater will cause a check engine light on many vehicles.