Took a trip to VA and back this weekend and on my way down my gen light came on, and I noticed that the alt was putting out at the very min of the normal range, but if I would crank it up to 5k and cruise for a min or two it would start back to 14-15-16. Its been doing that ever since then every time i start up the truck. Would driving for a few hours at 2500 spin the alt too hard? Time for new alt?

 

pull the alt out and take it to the auto store and get checked. might just be the belt slipping.