Well, you can add more trans cooling. Holding 2nd would have reduced heat. However, if your estimation of weight is correct you are overweight. I'm the last guy to say that towing at the max is a problem, assuming the other important weights are under. But this is a heavy rig, and I suspect you are more than a little heavy. Do you plan to continue to venture into the types of roads that caused the failure?
Any chance you can load it all up and limp it to a scale "as is"? Knowing the real weights on each axle would be telling. I think you could make a more informed decision that way.
Towing cap link
