towing capacity

I concur. The number you need to focus on is the payload, found on the weight sticker in the driver door. Even if you kept the real weight at 8,100#, your potential tongue weight is over 1000#, plus the 100# the WD hitch weighs. That's most likely the bulk of your payload. Add your wife, dog, anything you carry in your truck, and you'll be over your payload real quick.