Ray,

I don't know what Dodge or some of the truck forums would recommend but all over the rv forums it's buzzing with the problems that the DEF head failures are causing primarily because of the Shaw-designed units that are failing on both Freightliner and Spartan-built chassis. There is also a lot of talk about the DEF as well. Basically- everyone stresses to use the freshest stuff as possible, and that buying it in places like Walmart might not be the best idea. Many recommend topping off at fuel stations where it gets replenished more frequently. If I were you maybe look at the truck forums- I'll bet there's good stuff there too. I'd also try to see if you could drain what's in there now.

So far I haven't heard about any big problems with DEF head failures in the Ram truck forums I look at.

I had a reply in the YouTube comments that made me feel better about it.
"I work in the DEF industry and I can tell you it is incredibly stable for well over a year in all kinds of temperature ranges. You can top it off with fresh product and it will be perfectly fine."

Also, I read that lower temperature helps with lifespan. If the average overall temp day and night is 10C then the DEF is good for 3 years. Up here we get quite mild temps and most of the time we have been here has been on the cooler side. Sunlight seems to play a role as well. The DEF I got came from Canadian Tire last year and had a date code just a month or so old. It went straight into the truck so never saw any sun.

I've been doing some longer highway trips lately and have used some more DEF, likely down to a 1/3 of a tank so think I will now fill the tank with fresh and hope to get towing next month and using the DEF.

I have been using Walmart Def at $6.99 for the standard 2.5-gallon container in my DP for three-plus years now. A far as freshness goes, WM turns over inventory so fast you know their brand Def is going to be fresh. At one time Walmart Everstart Batteries were rated the best batteries to buy because they were the "freshest" batteries on the shelves.

If the OP would check out some other forums like iRV2 or ForestRiver there is some pretty extensive conversations on Def bought at Walmart and other locations.