Why is my battery out at 40K

[nglayton]

I bought my truck brand new from the dealer September 2011. Going on 6 years with my stock battery with no issues so far.

Ditto, Bought mine in March of 2011, of course adding a second battery probably didn't hurt.

 

[nglayton]

Are our OEM batteries sealed? I haven't looked.

No they are not. I just looked at my Panasonic, 6 screw caps. My water level is good, even after 6 years.