new 2500 gmc

got a 27rkl wc.pull it with a 1500 gmc 5.3 thinking bout a 2500 6.0 with towing pkg. had it out a few timesthis summer. motor screamed 4000-4500 rpms going over a few mts up here in upstate ny. truck really didnt squat much though. other than that she was running about 1500-2500 rpm. mpgs was about 10

I'm not sure the 6.0 will fare much better in the mountains. Any of the gas motors will have a time of it going up the hills. It's just one of those things. Depending on the mountains, even a diesel will let you know about it, but will handle the mountains much better. If you do a lot of towing in the mountains, I would suggest a diesel rather than a gasser. JMHO!

I Love my Duramax, it pulls like a train. and for me up against a gas engine it is cheaper to run.
Sean

The 6.0 will probably be turning over 4000 RPM’s going up mountain grades too. Gas engines develop their maximum HP and Torque at very high RPM’s My previous truck was a Dodge 8.0 liter V10 gasser and going up mountain grades in Colorado it would turn 4200 to 4500 RPM’s. Gas engines are designed to deal with high RPM’s. It sounds horrible though.

If you’re going to do a lot of mountain grades, you might consider looking for a diesel.

I have owned;
99 5.3L 1500 extended cab 4x4 Chevy (traded)
04 6.0L 2500 crew cab 4x4 Chevy (traded)
10 6.6L 2500HD Duramax crew cab 4x4 Chevy (just bought in July)


Not sure if the current 6.0L is the same as the 6.0L in my 04, but here are my thoughts.

The 6.0L pulled better than the 5.3. I had the opportunity to pull about 6,000lbs of hay 240 miles with the 5.3L right before I traded it in for the 6.0 in 2004. After the trade in I pulled another 6,000lb load of hay with the 6.0 the same route. The 6.0L had better power and got better mileage towing than the 5.3L. However, when unloaded, the 6.0L was a pig on gas, much worse in town and on the highway than the 5.3L.

Fast forward to this summer. I had a Dutchman 19T Hybird TT, weighing about 5,000lbs loaded. We took it on a 2,200 mile trip which included the mountains around Banff and Jasper Alberta Canada. Pulling with the 6.0L I averaged about 9.6 miles per US gallon. In the mountains it was much worse. I noticed going up a fairly steep highway between Banff and Jasper in the Columbian Ice field Highway, that the engine would drop down to 2nd and run about 5000+ rpm, just to maintain 60 Km/h (about 40mph). The truck had no more to give. THIS WAS A STEEP ROAD. This wasn’t so bad as the speed limit was 60km/h in this section anyways, but for the first time I felt I was underpowered. Even on the flats, the truck would shift down to 3rd on any little incline and 2nd on bigger hills.

The wife & I then decided it was time move up to a bigger rv, so we started shopping fifth wheels. I figured that it was time to get a bigger truck if we were to get a bigger trailer. I got a 2010 Duramax in July, and then we got a Wildcat 28RKSB in August. The Wildcat loaded up is about 9000lbs (estimate), and is much higher than the Dutchmen (12’4” vs 10’3”), and weighs about 4000lb more than the Dutchmen.

Pulling power is awesome. Going to the same campgrounds, about 100 miles away, that we usually went to with the 6.0L/Dutchmen combo, I am getting about 2mpg better with the Duramax/Wildcat combo where the trailer is 4000 lbs heavier. Power is amazingly better. Pulling up inclines the engine sometimes won’t even drop out of 6th and rpms stay in the 1700-1800 rpm range all day. It will drop to 5th once in a while on larger hills, but the rpms still stay in the same range. With the 6.0L and smaller trailer it would drop 1-2 gears and be in the 4000-5000 rpm range on hills and tach about 2000-2200 rpms on the flats.


The 6.0L was an OK engine. I’m not sure how it would have performed with the new fifth wheel, but I am sure it would have got the job done, just with some heavy fuel consumption and a lot of rpms. I think the newer 6.0L have a bit more horsepower & torque than the one I had. In all honesty, it was a fine truck. Only when we hit the mountains did I find it was lacking a bit.

Note: I have not had the new Duramax/Wildcat combo in the mountains yet. Next year hopefully should find out how the diesel performs in the mountains

I'd like to add one thing to Honkers post about the Duramax. When going down hill, the Allison transmission takes over and gives a very confident feeling of control. I think I like that feature the most in my truck. When we purchased the 5er a year ago, we were coming home and going down a VERY steep hill (the kind that had a run away truck pull off) and That Allison held the truck and trailer to a speed where I don't think I even touched the brakes.
Jim

our plan is to evenually travel with the 5er cross-country(within about 5 to 6 years)but in the meantime just travel locally within 300 miles at most. my sierra is an 08 5.3 12,000miles.its almost paid off.I get 13mpg round town, about 10 towing. the trailer is 7000 empty.

If you are going to stick with a gasser, then I would keep the current truck. You don't have many miles on it and it's almost paid off. Moving up to a 6.0 isn't going to help much, if at all.

When it comes time to take the fiver cross-country, then trade your current truck in on a 3/4 ton with a diesel in it. There are some very long and steep mountain grades when you drive through the Rocky Mountains and the power of the diesel takes on those grades easily.

I agree with moving to the diesel, I have an 04 GMC 2500hd 4x4 gaser and on steep inclines I'm waiting for pistons to come through the hood up into the 4000rpm range. I have figured out how to feather the gas and get the transmission to change when I want it to so I don't get those 5000+ rpm runs up hills anymore. I hate feeling underpowered on hills which I think I am.

Wow GustheUsher...yeah, I think you have definitely bitten off more than you can chew. The 6.0 is a commendable engine, but I think you're asking a bit much of it with that trailer. Time for a new truck!