You guessed it right. I also have to purchase some batteries this week. Right now, if I leave it set for 4 days, it barely turns over to start. These are the original Delco batteries that came with the truck. Manufacture date was July 2001. 5.5 years isn't too bad, I guess. I will either be getting the Optima red tops or the Delco's.BRUCE;1541159; said:04 GMC , last couple weeks when I start truck clock on radio is back to 1200. Have to reset most of the time. I'm wondering truck seems to turn over just a little slow at times, maybe power drops down and radio thinks batterys are disconected? What ya think?