2009 GMC 2500HD 6.0gas 6spd 373gears 4x4 with airbags

[coodle0216]

Looking at buying a Glacier Peak 5th wheel with maximum weight capacity of 11,000 pounds. We figure it might be a little on the heavy side. If anyone has this setup of truck and this weight of 5th wheel and has any suggestions/opinions, please let us know. This truck only has 25,000 miles on it - like new and is paid for. Do not want to change trucks. Don't know if changing gearing to 410 would help that much or not - any opinions ? Thank you in advance for any answers.

[MHWASH]

I got 6mpg no matter if I was on the open road, or taking a back road up the hills. Never had any trouble with it, just made me real nervous.

[APT]

rwess wrote:
With your proposed 5th wheel with the extra frontal area that sticks up above the truck, I would not be surprised if you are in the 6 MPG range.

Most 5th wheels do not have extra frontal area over a TT. They have a little more over the cab of the truck. A TT has air hitting from the bed of the truck. It's about a wash.

MHWASH wrote:

We had a '09 CC, LB with the 6.0L. It pulled our 24'TT just fine. Then we upgraded to a 31' TH @ 9500 lbs. RPMs were constantly in the 3000-3500 range on any kind of hill. It got an avg. of 6mpg towing. I was concerned with longevity of the motor and tranny running those high RPMs all the time. When the tranny would shift down going down grades it scared the******out of me. I don't ride my brakes, but just trying to slow down a long grade would cause the tranny to shift, similar to the Allison, causing the motor to increase its speed by about 1000 RPM. I got in the habit of shifting in to manual mode going down hill.

That all sound perfectly normal for a naturally aspirated gas engine, except the 6mpg seems really low unless your speeds were more like 70-75mph.

Grade braking (trans downshifting) is purposely designed to keep your truck brakes a little cooler.

3500rpm is about 800rpm lower than peak torque. If you were trying to hold 65mph up hills, 5th gear won't do it at 2200rpm, so 4th gear at 3000rpm seems right. But my truck with same powertrain hold most hills in 4th gear at 3000rpm and I can accelerate in 3rd at 4500rpm. The GM 6.0L is designed to run 5500rpm, although using a lot of fuel.

[MHWASH]

We had a '09 CC, LB with the 6.0L. It pulled our 24'TT just fine. Then we upgraded to a 31' TH @ 9500 lbs. RPMs were constantly in the 3000-3500 range on any kind of hill. It got an avg. of 6mpg towing. I was concerned with longevity of the motor and tranny running those high RPMs all the time. When the tranny would shift down going down grades it scared the******out of me. I don't ride my brakes, but just trying to slow down a long grade would cause the tranny to shift, similar to the Allison, causing the motor to increase its speed by about 1000 RPM. I got in the habit of shifting in to manual mode going down hill.

[rwess]

I have a 2010 2500HD 4x4 3.73. I just finished an approximate 800 mile round trip from just west of Atlanta to St.George Island, Fl. I got 7.8 going and 8.2 coming home (very little interstate only I-185 from LaGrange to Columbus). I tow a 36 ft. trailer that weighs around 9,000lbs loaded. With your proposed 5th wheel with the extra frontal area that sticks up above the truck, I would not be surprised if you are in the 6 MPG range. The 6.0 can tow, you have to put your foot into it, but it is very thirsty and I only have a 26 gallon tank. I took a 1200 mile trip in June, mostly interstate and got 7.6 mpg.

[rhagfo]

coodle0216 wrote:
We have an extended cab, short bed truck. We installed the airbags just to keep the truck level.
Thanks !! 🙂

Does the truck normally sit level, or tail high unloaded??

[wintersun]

GM rates the trucks with the 4.10 gears a full 25% higher than the identical truck with 3.73 gears. Changing out the gears is a smart thing to do and a lot less costly than buying another truck. You will be reducing wear and tear on the engine and the entire drivetrain. I would also expect no reduction in fuel economy when towing with the lower gears. You will also want to have a WDH for the truck with that amount of load.

Current model GM 2500 trucks with the gas engine and 4.10 gears are rated for a maximum total load of 13,000 lbs. so you are pushing it to tow 12,000 lbs. on a regular basis or in mountainous terrain.

I would be most concerned with the transmission and options include a larger pan so the ATF capacity is increased and upgrading the factory transmission fluid cooling unit.

[Mr_Beebo]

My 09 has the 4.10 gearing, and was previously set up for a 5th wheel. It is rated for 14,200lbs. I now pull a TT only but I have had weights up to and past 12k. No issues with acceleration in or out of the mountains. We were recently at a dead stop on a very steep switchback on a backroad in the Smoky Mtns and it never missed a beat. Acceleration is not a problem. The 23 gallon tank, well...

[kmbelt]

coodle0216 wrote:
We have an extended cab, short bed truck. We installed the airbags just to keep the truck level.
Thanks !! 🙂

You are only rated for 9,900 lbs with the trucks current configuration.

[coodle0216]

We have an extended cab, short bed truck. We installed the airbags just to keep the truck level.
Thanks !! 🙂

[Sandia_Man]

Going with 4.10 gearing will certainly help but may not be required. We tow 10K rig with our 3/4 ton Chevy gasser (with 4.10) and it handles it well. Enjoy your new rig and if towing performance is less than you expected you could opt for the gear change.

[goducks10]

coodle0216 wrote:
Our dry pin weight is 1440. Thank you for all your info and answers!! It has helped alot.

OT but please come back if you do buy the Glacier Peak and let us know how you like it.

[B_O__Plenty]

Don't get too excited about the airbags part. They do not increase the load carrying capacity. They are only there to level the truck.

B.O.

[Grit_dog]

Chassis and drivetrain will handle it fine. If you tow in the mountains it will be a slow journey up hill. Otherwise good combo.

[kmbelt]

what is your cab configuration (reg, ext, crew) and bed length (long or short)