How long of a life have can one expect out of their batteries in their diesel pick-up? My truck sits quite a bit these days, and one time last winter when I went to start it, the batteries were dead. It has been taking longer to start lately (like cranking for 5 seconds), when it used to start right up with just barely a turn of the key. I replaced both batteries in the summer of '98, so the batteries are now 5 years or so old.
1993 K2500 133,000mi,<br />4.10 gears, 4L80E, 3.5\" exhaust, EGT& Boost gages, intercooler, TurboMaster, no snorkel, Amsoil air filter.