Got the 41 Gmc on the road ,3/4, and noticed as soon as I get going the amp gauge needle disappears into full charging land and does not drop down until I turn it off. The truck is still 6 volt, postive ground, the generator has been checked twice and the voltage regulator replaced and polarized, it has a new harness also. At idle the gauge has a slight charge, when I hit the lights it discharges, engine not running. Everything seems normal but it does not seem right for the needle to go off the scale. Am I overworring this?