Towing capacity increase

My 2008 GMC Sierra Extended Cab Standard Box 4WD 5.3 Flex fuel lists my max trailer towing capacity as 7500lb and GVWR as 13,000.

The same model in 2011 lists max trailer weight as 9600!

How much of this increase has anything to do with changes to the vehicle, and how much of it is just increased due to more thorough testing and the fact that Ford has been boasting 10,000 for their 1/2 ton?

Also, I have the 3.73 gear ratio; if I had the 4.10 I could tow 8,500.

The 2011 that tows 9,600 has 3.42 ratio, using the logic that higher is better, shouldn't mine tow even more than the 3.42?

One other thing, I have the Heavy Duty trailering package. There is no reference to this in the manual, does this add any towing, or if you don't have it you should subtract?
I have the 4 speed transmission, not the 6 speed, but the towing capacity doesn't reference transmission type, so I don't think it matters.

I made the mistake of thinking I had 8,500 capacity and purchase a 7000lb camper, when loaded I will be pushing the limit if not over by a few hundred. I don't want the mileage decrease or cost increase of a 2500, and I don't want to buy a new 1500 and find out there really isn't much difference.


Any thoughts/comments are appreciated, and facts even better!

A lot of the difference has to do with the frame, the way it is sprung and the axle.

Trans cooler, dual Electric fans, etc....

Do what I did: I have a Sierra 1500 with 6.0 liter and I've got an cold air intake and throttle body spacers installed, she pulls with 5500 lbs as if she's empty. I have gone higher but that was a one time shot for my buddy...not sure what the load was but I know it was much more than my usual trailer!! I also have (this is the most important part) a Firestone Air-Ride system installed on the rear axle which means when I put that load on her she won't drop an inch and handles like a dream. I also have a trans cooler installed.

The best part to all this? Do it yourself:
Air-Ride guide
http://www.firestoneindustrial.com/pdfs/newsrelease/Riding_on_air_TrailblazerMarch2007.pdf

Andy's automotive is a good site for finding the parts you need but there are also many other great online sites, you may find one closer to you and reduce the shipping time. Grab a cold beer and sit in front of the computer for awhile. Ah, why not make it two beers? You can do this on a nice sunny day, I always start at 7AM cos you never know what snagglepusses you'll find in the hedges today

I towed the trailer north over the Memorial Day weekend. Other than taking a little longer to get up to speed it didn't feel too much different from the 4000 pound trailer. The weight distribution hitch does its job to prevent any squatting so I don't think I need air shocks. I can feel a little more bounce at times with the extra tongue weight; I suppose air shocks could help with that.
Checked the transfer case temp several times, it wasn't any higher than it was with the old trailer either.


I would love to hook up a 2011 1500 to the camper too see if I could tell any difference, I have a feeling they didn't do much of anything other than test heavier loads and bump the number up.

I would be happy to look into this for you as well. In order to do more research, I will need the VIN for your vehicle. Please feel free to contact me via private message as well. Thank you in advance.

Tricia, GM Customer Service.