Chevy 2500 HD 6.0 question

jkilroy wrote:
I’m towing a 7500 lb. Cougar 28SGS. The truck I have is a 03 Silverado 2500 HD 6.0 with 4.10 rear. This rig tows fine in cooler weather with no A/C and fairly flat to moderate hills. When I pull in decent mountains and it’s hot the trans temp climbs past 200, and coolant goes to 230 range. As soon as I turn off a/c everything is fine. Has plenty of power I must say. I usually set rpm to 3000 and let it run.

So question is can I do anything to truck to help the problems? Can I put a cooler thermostat in it? I’ve already added a second trans cooler. It helped a little. A diesel is in my future but I’d like to pay off camper first if possible. They are so expensive.

All the other guys have given you excellent advice. On the RPM, though, you need to run that up into the 4's, that's where a gas engine makes the most power and will work "easier". At 3k, you're likely lugging the engine some and it will work "harder", even at a lower RPM. I've seen this with my own eyes on a trip with an old truck pulling a 3-axle GN up over Cajon Pass and Tehachapi. Not only did the engine run cooler at a higher RPM, mileage =improved= slightly. This was with a 600 RPM difference on a Turbo 400 with GearVendor O/D running the same gear with the O/D on and off. Don't be afraid to run the RPM up and hold it there in whatever gear you can hold. Downshift if you have to to keep that RPM.

I just checked, and that engine (2003 6.0l Vortec) specs at 300 h.p. at 4400 RPM and 360 lb ft torque at 4000 RPM. So, run her up to 4400 to get max hp.

Lyle