The GCWR for a 2010 Suburban 2500 ( 3.73 gears) & the 6.0L gas engine ... is 16,000 pounds
The GCWR for a 2010 Silverado 2500 w/3.73 gears & the 6.0L gas engine is........16,000 pounds
The max trailer weight rating for a 2010 Suburban 2500 4x2 is.... 9600 pounds
The max trailer weight rating for a 2010 Suburban 2500 4x4 is.... 9300 or 9400 pounds (depends on whether you look at 2010 or 2011 model year brochures)
The Suburban 2500 4x2 weighs 6179 pounds , the 4WD weighs 6447 (268 pound difference) - that's where your 300 pound difference in tow ratings comes in.
The max trailer weight rating for a 2010 Silverado 2500HD Crew cab Long box 2WD is...... 9600 pounds
The max trailer weight rating for a 2010 Silverado 2500HD Crew cab Long box 4WD is...... 9400 pounds
The Silverado 2500 Crew Cab long box 2WD weighs 6027 pounds, the 4WD weighs 6308 pounds
All of the trailer weight ratings - and the GCWR numbers - are directly out of the GM brochures or other publications.
The important point here is that the published weights of a Suburban 2500 & a Silverado Crew Cab long bed are pretty close between the 2WD & 4WD versions - and their published trailer tow weight ratings are the same and vary the same between the 2WD & 4WD versions.
Then - from the very same Chevy Silverado HD brochure that the numbers above were taken from - this is what the rating goes up to simply by going to the 4.10 gears:
GCWR : 20,500
max trailer weight (ball hitch) = 13,000 - 13,600 (varies depending on body style)
The GCWR for the Suburban 2500 & Silverado 2500 with 3.73 gears and the 6.0L drivetrain - are the exact same. The trailer tow ratings vary because the vehicle weights vary.
As a further example of this - the max trailer weight (ball hitch) for a 3500HD Big Dooley Long Box 4x4 - with the 6.0L gas engine and 3.73 gears - is only 8700 pounds - a full 600 pounds LESS than the Suburban 2500 4WD. It's because the dually model weighs heavy. The 4.10 gear ups the rating on the dually 4x4 to 13,200.
I can tell you for an absolute certainty that the full floater 10.5 " axle that is in the back of the GMT900 Suburban 2500 & the Silverado 2500 is the same exact axle. The only differences are spring and shock mounting points. GM doesn't go around producing axles of the same family - with varying weight carrying capacities. If the GAWR weight rating varies - it's because of spring rates, or the weight of the vehicle that the axle is mounted in - not the load carrying capacity of the axle unit itself.
And I'm sure the GAWR for the Silverado models varies depending on the body style. Single cab short bed vs crew cab long bed are different weights - I can't find the GAWR numbers for all of the different body styles of Silverado pickups.
The GVWR is not the tow rating. But you should take it into account when figuring out what how much trailer weight you can pull - if the vehicle is loaded down.
For example: If I take the 16,000 GCWR of a Suburban 2500 4x4 - and subtract out the weight of the vehicle (6447 pounds) and a 250 pound driver weight - I get 9303 pounds - which is pretty much exactly the trailer weight rating for the 4WD configuration.
The numbers show that a GMT900 Suburban 2500 - should be easily capable of towing more simply by changing over to 4.10 gearing. If there's a restriction on the trailer weight - it's going to come from the truck frame. The GMT800 8.1L Suburban 2500 models were rated to tow 12,000 pounds. So that's the highest factory trailer tow rating ever applied to a vehicle using that frame.
