John, going with a tag trailer at those weights is too much for a srw truck. I have an srw chevy and moved a 10,000lb skid loader on a 4,500 lb tag. It sucks. I have moved a case 580 with it as well and it is so much worse. White knuckle rides. It is not worth the risk of losing the truck and trailer not to mention all the insurance issues that come along if the trailer separates from the truck. Those weights will push that truck and it is so much more important that the equipment is placed in just the right spot.
I guess it boils down to; can it do it? Yes. Is it comfortable and safe? No.