Specs say max weight is 5000lbs, 500lbs tongue weight. I tow a 3200lb boat. When I take it on vacation, I load all my crap into the boat, so I've probably broken the 4000lbs mark. I tow with the V6, 3.90 gears, 32" tires, auto transmission, and a TRD tranny cooler. I could use some extra power now and again towing that kind of weight, but the rig doesn't show any signs of mechanical wear from it.

I do highly recommend a tranny cooler if you're running an auto transmission.