SO WHAT rules is he overweight by? The local codes that the LEO enforce? or RV/nets weight police?!?! Reality is, both to a degree need to be looked at, but at the end of the day, the truck in question is out of warranty, so might as well build up the now found weakness, which would have failed even with a dually mind you, that MAY have a larger warranty/engineer blessing of what it can do.
Even if it WAS under the gcwr/gvwr ratings, the OP may very well have fried a trans due to the steepness of the grade, and not running the tranny in the correct gear etc. So one can fry parts even with in the manufactures specs, due to the fact you are soing something at the end of the day, beyond those specs. IE if on a grade steeper than 12%, you are BEYOND, out of spec of the new SAE tow rating specs, and would probably blow up your tranny!
So at the end of the day, which do you do? I'd rebuild it, better if you can, if you can go to some lower gears in 1-4, will assume 5 and 6 are direct and OD, that will help you get some more torque to the rear wheels, possibly keep the TC from spinning as much getting going etc, may make the rebuilt one last longer, along with the things perrybury mentioned too. I also fried a tranny when I was at 12K gcwr with a rig rated to 16K. BUT, the rig at 12K could not climb more than a 15% grade, I was needing to go up a 20+% grade.......never trusted that rig again! went thru TH400's like clockwork every 30-35K miles, even with 5K fluid, and 10K total flush's of the tranny! Geared too tall in the trans!
Marty
