help with towing 5th wheel

[jmgrafix]

i have a 2010 gmc 2500 hd crew cab,6.0 gas,6 sp trans 410 rear axle.my owners manual say i can tow 12300 and pin weight up to 2500.............the 5th wheel that i am looking at is 10100 dry and 2100 pin weight, the waqy that i read the manua,l i am ok............. what do you think

[therink]

Hi
You need to find out what the actual gvwr of the fiver is, which is likely around 12k. Ideally, 20% of that 12k will be loaded pin weight; around 2400 lbs.
The gvwr of your 2010 sierra 2500hd is posted here: http://www.trailerlife.com/wp-content/uploads/2012/01/DigitalTLTowGuide2010i.pdf

The payload rating for your truck (gvwr minus curb weight), can be found here:
http://autos.aol.com/cars-GMC-Sierra+2500HD-2010/specs/

The payload rating for you truck is likely around 3200 lbs. So if 2400 lbs if pin weight, you will have around 840 lbs left for passengers, dogs, firewood, 5er hitch, tools or anything else you carry in the truck or bed. You are cutting it close withe that set up.
I had a 2008 2500HD with the exact same 6.0 and 4:10 axle, ext cab. I scaled it with my current 12k fiver and found that while I was not exceeding the max tow capacity of the truck, I was exceeding the gvwr of the truck (payload) by a few hundred lbs. I was also exceeding the trucks 18,000 lbs GCWR.
With this in mind, last year I upgraded to a 2012 3500hd with exact same power train. I am now within my limits with room to spare. GM also beefed up the frames in the 2011+ HD trucks. My 2012 3500 is night and day with towing from the 2008 2500 I had.
Good luck
Steve