So I have had the rear end replaced twice now in 1500 miles and its ready for a third. All I do is tow with the truck, it gets driven very little otherwise. I have put a larger cover on to hold more oil and that didn't help. When I tow I can smell the fluid burning up and if I throw water of the diff it boils off. Obviously it is getting so hot that the fluid fails and the gears go because of the heat. Chrysler is unconcerned with whats causing it they just keep replacing it. My question is what is causing the heat build up? Can someone explain how the axle and rear end work together and what would produce the excessive heat? I would like to go in for the third swap out prepared and get to the bottom of this. Thanks.