I have a 2004 GMC 2500 Duramax. Been debating whether or not it would be safe to tow a Donzi 38 ZR 525's on triple axle Myco trailer 350 miles to LOTO from SW IA? Estimating boat at 8500-9500 lbs and trailer at 2500 lbs. for approx. 11,500-12,000 total lbs. Truck is rated at 12,000. I've been told no problem and I've been told better not. Also, I have a hypertech power programmer that I will remove so that it will be back to stock for the trip. It's borderline, but I seriously don't want to screw up the truck. What do you guys think?

I'd do it, just make sure tires and brakes are good, any hills/mountains to deal with?

Flat I-29 for 75 miles then it gets hilly in MO. No mountains.

no problem i did it with mine

I pull my 89 F 35-7 with a 2005 sierra crewcab 3/4 ton 4x4 duramax. Boats and trailer weights 14060 pounds and has 1220 pounds on the tongue (hitch). Works fine, run 65-70 mp/h and honestly dont really feel I'm pulling something.So 12000 is definatly ok. By the way I'm not even using hypertech... Hope it helps!

i pulled a dump trailer with mine went across the scales at 24000 yes a little to much but it pulled it fine, trailer had electric brakes and i took it easy but it pulled it with ease

not a problem.

close eye on tires and pressures

also on trailer bearings

Check to see what your hitch is rated at. I replaced my stock hitch with a Titan class V. The stock hitch seems to be the weak link. The 06 2500 HD Duramax is rated at 16,100 towing.

Ditto on what Rippem said. Remember to let the trailer bearings cool down before launching.

Dan

BTW you are not going to hurt your truck it's a DMax!

and leave the power programmer on it, thats why you bought it, to optimize performance and towing.

I wouldn't use the Hyper unless you have a Pyro/EGT because exhaust temps will be high. That's why I bought the Edge W/Attitude because of the Display and backdown mode for high EGT temps.