I say if you don't tow often and far you won't have any problems. I sometimes tow 7000 lbs and do alot of towing with lighter loads. I don't know what my GVWR etc. is I just hook it up and go. I do have electric brakes on my 18 ft car hauler, and hydraulic ones on my big boat. I used to tow 5000 lbs with a 4 cyl. ranger auto so 7000 is no sweat for a 1/2 ton. You do have a factor of safety built into all of the parts.

If you tow 7000 lbs every day or even every weekend I would consider changing gears or another truck.