I ve picked up a new sound this past week and I believe its coming from the transmission only dose it when your pulling a load but just running down the road its ok no noise. When I first get started in the mornings it seems ok but once truck is warmed up then I hear it. I got under it when I got home today and transmission was hot to touch. I understand there going to run with some heat but how much is to much ? Seems like I work a week then fix a week anymore