Chum lee...you bring up an interesting question. The chassis mfr states a 10,000 lbs towing capacity. I was just assuming that I have a maximum tongue rating of 1000 lbs based on the 10% ratio. Maybe my hitch is rated for more but I cannot find anything stamped on the hitch to verify that.
By putting the SUV in backwards I can get the tongue weight down to about 1200 to 1300 depending on what misc stuff I have up front.
The trailer loaded is about 8000 lbs and tows exceptionally well. I pretty much don't even know it is there even in windy situations.
I am going to keep searching in the manuals for hitch information.