I built a custom rig for personal use and I recently had to use it for the second time. I recently went from east coast to west and back again.

It's my first diesel and I have some questions to try to get it to perform better and not get hot.
(Not sure if changing the final drive ratio is the way to go or not. And I surely have no clue what the sweet spot is to run the 6.5 turbo diesel at.)

FYI - It was an ambulance, well maintained, only 19,100 miles when I got it. It now has 30,566, on the 6.5 turbo diesel, after using it twice.

What I do know is if I kept it around 60mph it ran great. However, if I pushed it to get somewhere faster - it wanted to run warm - close to hot - as if the engine RPM were high. When I added a load on the truck and trailer and had the mountains to deal with, out west, it was worse. (If it were gas, I would feel comfortable changing the final drive ratio. But since it's a diesel and my first - I need more info to understand what would be best to do.)

BTW - It came with GT5 - Axle Rear (Dup of GT8) 4.10 and G80 - Axle Positraction, Limited Slip..

Thanks


For those who have not already seen my build page and want to know more about the build process. My G3500 Toy Hauler - Chevrolet Forum - Chevy Enthusiasts Forums