[Rivergoer]

...however I don't want to get stuck somewhere with a dead battery if it is indeed in need of a replacement.

Any thoughts?
Thanks.

Had the same thoughts as you recently.

I opted to replace my still-functioning ‘14 CTD factory ACDelco AGM battery last month (Oct). The date code was June 2014, car first went into service August 2014. So after 40 months on a “36-month” battery it was likely due.

Went with the Deka (East Penn Mfg) Intimidator AGM. Local battery store had to special order it as they normally sell the cheaper sealed, maintenance-free batteries. I didn’t shop around so I’m sure at $262 (incl. tax) I paid premium but it was worth it just to drive up and have it done, no worries.

Immediately noticed much faster cranking. Also fewer revolutions required before ignition (not sure why, perhaps glow plugs warming up faster?).

Would the original battery have lasted another few months or a year? Possibly. But why risk it? After over 3 years of service and reading stories of diesel battery issues, I figured I’d get the battery replacement done on my terms and at my convenience.

With winter coming, it might be wise to pull the trigger now...