Trailer weight

I own a 2004 Chevrolet Silverado 2500HD, 6000 V8 engine, 4 speed HD automatic transmission with Tow/Haul mode, and heavy duty towing package. It’s top line equipped with absolutely every option Chevy offers. Current milage 8900 miles.
I would like to tow a 14800 pounds , fifth wheel, RV trailer (total weight loaded).
Chevy states in their literature that my truck’s max fifth wheel trailer weight is 10100 pounds. My question is: Can I tow this RV trailer I want to buy with my truck? Can it handle it?
I noticed that the same truck, with the same transmission, but an 8100 V8 engine is certified for 15100 pounds by Chevy. So the transmission appears to be able to take the weight, as is the truck. So it looks like it boils down to the engine size. Now, I don’t mind going slower...
Can I use my truck with this 14800 pounds fifth wheel trailer?
I fully understand that you can not endorse exceeding the manufacturer's weight guidelines. So I will treat your answer as just an off the record unofficial opinion.
Many thanks.
Christian Joffson, Jay, Vermont.  

As it stands, no. For a couple of reasons, the first is weight capacity. That trailer needs about 3000 lbs on the hitch to pull right and that will over whelm your truck as it lacks the springs and the tires to deal with it safely. You could add a few leafs to it and install 265E range tires and that would fix that because it has same frame as a 3500 and rear axle itself can handle 4 tons. This leads to the next problem, power, you really do not have it. You mention the 8.1 tow rating, it is a completely different animal towing and has goobs or torque and uses the allison 5 or 6 speed with a much deeper first gear (3.1 vs 2.48) and a much deeper reverse (4.49 vs 2.07) so not only does it have more power it has better gears too. Quite honestly even with 10,000 lbs it will struggle at times (especailly on hills) even with a 4.10 axle ratio which is really not that deep for your tire and vehicle size powered the way it is. You could regear the truck with 4.56's or 4.88's and give it a fighting chance as it would move it with deeper gears and higher octane fuel (your ECM will really retard spark pulling that weight with 87 octane fuel and cut power in process) You basically have three choice here, get a smaller trailer (about 9K or so), get a bigger truck (a dualie would be much better choce here for this weight), or modify truck as stated above and you might get by okay if you do not take any trips through rockies with it. If you try it as is it is  going to be trouble. Sorry that I do not have nice words about it but this is the straight scoop.

Hi, many thanks for your reply. I understand what you say. However, the tow rating I quoted for the 8.1 (15600 Lbs) is with the SAME trany I have, not the the Allison. The Allison is an option. So it might appear that the trany should be able to handle the load?
The difference is the engine. 300 on the HP versus 330, and 360 on torque versus 450.
You don't think that the springs or the tires are good for the load either?
Thanks. Chris.
 

Never seen a 8.1 with a 4L80 so I am not sure where you are getting it. It is not that the 4L80 is a weak tranny but it has its limitations and when you compare your truck to one with a 8.1 you have a much taller first anf reverse which reduces tractive effort and a lot less engine torque too. THe 8.1 is strong from about 1500 to 4000 RPM and it reaches it torque peak by around 3000 RPM where it can be very effective towing. Aslo when you compare the torque difference, remember this while you have 360 vs 450 at flywheel in theory, you have less than thios at 3000 RPM on the 6.0 because it has not reached its torque peak pulse it takes so much power to overcome drive line losses and moving the truck without the traile and the extra 90 ft lbs of torque it a lot more in real world performance because it is availble at a lower RPM and it is on top of what the 6.0 can actually put to rear wheels so the net result may be 35 to 45% pulling power instead of the 25% difference that numbers suggest. The 8.1 in a beast towing with a 4.10 axle plain and simple. On the tire capacity, without doubt the stock tires are not up to it as at least 265 x 16 "E"'s are needed for a combined capactiy of 7000 lbs for rear tires. On the springs, no doubt there regardless on factory rating because GM has takne a 99 old style 8600 GVW CP^/HD 2500 anf morphed it into a 2500 HD and removed one leaf from each side in rear to make it ride softer for sales and then raised the "rated" GVW to 9200 lbs for sales. You place 3000 lbs in the bed of that truck on the hitch and it will sag badly and worse than a old 8600 GVW truck would.(few people would notice this and take the rating verbatum) I have a 2000 K3500 SRW old body style that I bought new and it has a 9200 GVW rating too and guess what, it has more springs in rear than the like rated 2500 HD. (it rides ruffer empty because of this but it hauls weight a lot better too). You hitch up the trailer to your truck as it sits and you will not be happy with weight carring or towing abilty. It will be a bad experiance.

Thanks snoman for all the time you took to explain all this. I really appreciate it!
If there is anybody out there that has actually done, or is doing heavy fifth wheel trailer towing with a K2500HD with a 6.0 motor, I wouldbe grateful if you could share your experience also. Thanks.  

No problewm. I like GM trucks, I just do not like the direction they are going in sometimes. Also it is not just GM, Ford has done the same because if you compar like model Ford pre 2000 and current, you will find that they removed leafs from them to to make them ride better to sway more potenail buyers. If your heart is really set on a 14k trailer, you need a different truck to pull it. If you want to keep current truck, limit trailer to about 8K lbs or so if you plan some long trips and maybe 10K if you are going to be "local" with it. Sorryif I sound like a downer here, I just want you to have a safe and "fun"  experaince, not a bad one.