Forum Discussion

Explorer

May 29, 2016

What raises the GM 2500HD tow rating to 13k besides 4.10's ?

I've searched all over the internet trying to figure this out and thought somebody here might know the answer to this question:

The trailer weight rating for the GM GMT900 generation (2007-2014) 2500HD and 3500HD pickups with the 6.0L gas engine (Silverado or Sierra), go from anywhere in the 9000-9700 pound range ( varies depending on body style).

It lists the trailer weight rating for the 4.10 ratio as 13k pretty much across the board.

You can pull the specs from page 10 of this brochure:
http://www.chevrolet.com/content/dam/Chevrolet/northamerica/usa/nscwebsite/en/Home/Help%20Center/Download%20a%20Brochure/02_PDFs/MY13%20Silverado%20HD%20eBrochure.pdf

So the question is: What else (if anything) changes on the truck to increase the trailer weight capacity to 13k besides the gear ratio?

I've searched high and low trying to figure this out and asked a few GM guys I know and nobody can give me the technical details.

From what I can tell searching thru parts suppliers - it doesn't look like there is any bigger brake option. The part numbers for front and rear rotors on all Chevy 2500 & 3500 pickups and the 2500 series SUV's - are the same.

There are slight ratings differences in the HP and torque between the 6.0L in the trucks and the 2500 SUV's - but no published difference for the extra tow capacity.

I did find a listing for an electric cooling fan setup for "enhanced tow package" for the 6.0L trucks. I know the standard setup is an engine driven fan.

The 2500HD pickups and the 2500 SUV comes with the 6L90 transmission, so there's no bigger transmission to go to except for the Allison - and only the diesels get those now.

So is that all it is? Is there just some extra engine cooling in the form of electric fans and the 4.10 ratio in drivetrain?

Tow Vehicles

25 Replies

SouthpawHD
Explorer
May 29, 2016
Try posting your question on GM-trucks.com, lots of knowledge over there. They have separate SUV and truck sections as well.
calsdad
Explorer
May 29, 2016
With the Chevy 6.0L engine at least the HP and torque numbers go up some as the RPM's go up. Reading thru some other forums I've seen numerous people say they see the rpm go up 200-300 on the tach at highway speeds going from a 3.73 to a 4.10 ratio.

I haven't sat down and mapped the torque and HP curve to the RPM rise though to see what that gain is.

The reason why I'm asking this is that I just picked up a 2010 GMC Yukon XL 2500. Which is basically a 2500HD with an SUV body. It has the same 6.0L engine and the 6L90 transmission as the 2500HD pickup. I believe the rear axle is the same also.

My line of reasoning is that if the factory has a formula (component list) to raise the tow rating to 13k, I should figure out what the formula is and use it to beef up this truck.
spud1957
Explorer
May 29, 2016
Ford is the same with the 6.2 gas. Go from 3:73s to 4:30s and the rating goes from 12k to 15K.

The engine runs at a more efficient RPM seems the obvious. Less strain on mechanical components? Less lugging? Better cooling? I'm not a AE so what do I know.
calsdad
Explorer
May 29, 2016
kw/00 wrote:
From what I have read over the years, its only due to the 4:10 gear set. I have the 3:73 and have pulled more then the rated 9800lbs... and still stayed within the payload limits with zero issues.

That's what I'm trying to figure out. I've asked the question in a few other places and gotten all sort of what I'll describe as "opinions". I'm looking to see if anybody knows the technical details.
kw_00
Explorer
May 29, 2016
From what I have read over the years, its only due to the 4:10 gear set. I have the 3:73 and have pulled more then the rated 9800lbs... and still stayed within the payload limits with zero issues.