Hello fellow truckers. I am the proud owner of a 2005 Chevy Silverado 3500 dually with a Duramax. I purchased it because I was sold on the Allison Transmission. I had a Ford 03 ford 3/4 ton as was told the trans was shot at 50,000. I was hauling a 43 foot fifth wheel regularly. So here I am 13 years later still driving the PU. I now haul only a 25 ft trailer so probably dont need the diesel any more but just love my truck. Just over 200,000 miles and other than it is not as strong as it used to be runs great. Have had no mechanical issues although did have the wireing harness replaced by factory one month ofter purchase. I do have one concern.. My batteries were dead. (left flasher on over night) I attached battery charger across the provided grnd and positive connection and charger only showed 6 volts. I had to disconnect the aux battery from system to charge and charge primary directly.. Is this Normal?