I got 10 years out of the OEM Motorcraft batteries in my 1996 F250 7.3L diesel. The OEM batteries in my Ram are shot now and need to be replaced; they've been so so for over a year now.
I'm going to replace them with batteries from Costco. Their price is good and their warranty can't be beat. A couple of years ago the alternator went in my wife's Acura MDX and took the 5 year old Kirkland battery down flat. I charged it manually a couple of times but the car cranked slower and I knew it was just a matter of time before it failed. I bought a new battery from Costco and took back the 5 year old one just to get my core charge back. Imagine how shocked I was when I was told there was still warranty on the battery and I got almost 50% of the original purchase price back! That has sold me on their batteries!
