10K pounds GVW? What axle are you running under the rear. If you look to gross out at 10,000 pounds, you definitely need at least 8 ply tires. Pop your rear hub cap off and look at your axle. If it's a full floating axle, yes, you can go 10,000 pounds. That will have a portion of the axle sticking through the wheel. The axle doesn't carry the weight on those but the heavy wheel bearing does. If the axle is flush with the wheel, you have a semi-floating axle. On these the axle carries the full weight in the rear.
My Class B weighs in at 6100 pounds with a full fuel tank but otherwise empty tanks and a semifloating axle. A 4 or 6 ply truck tire will work on these. I've had numerous Dodges through the years and they are really tough trucks. I've also seen semifloating axles snap from being over loaded.
