This has been discussed......about 1000x on here and usually starts an argument.
But here's the facts.
Aside from an Aisin trans, you have the heaviest duty, most capable drivetrain offered. Same as offered in a 3500drw configured the same way, with tons more payload on paper and much greater towing capacity on paper as well compard to the 2500.
You have the same chassis as the above mentioned truck, minus the extra back tires and different rear suspension design.
You have the same rear axle that is rated from 6500 to up close to 10klbs depending on what class of truck it's in.
And most importantly, you have the truck sitting in your driveway.
The short answer, is with some rear suspension help, it will pull a 14k 5ver as well and as safely as anything on the road save for a drw truck (which is nice, but not necessary for your pin weight). You will also be under the real world ratings of all the important components (axle, tires/wheels, chassis, drivetrain), but over weight on paper on almost all of those criteria due to the truck being marketed as a class 2 truck.