<flame suit on>
I towed my
L3430 with backhoe, loaded tires, etc... including the trailer, it was about 13,000 lb load. I towed it with my Jeep Grand Cherokee, which is rated for 7,000 lbs!!!!
Starting was slow but steady, stopping wasn't too bad with the brake controller for the trailer. Had to have the tractor in the right spot to get the weight distribution on the trailer where it wouldn't be wagging the dog so to speak. Bumps in the road SCARED the crap out of me as I was afraid the springs in the back of the Jeep were going to shatter.
I had a 2 hour drive each way, down all back roads and one short section on the highway. Speeds were definitely kept below the speed limit.
Now I've driven all across this country on just about every terrain, in every weather condition imaginable, once being the designated driver in a 15 person van (with 13 drunk fraternity brothers in the back) driving through lake-effect blizzard conditions on strange roads. I've been off-roading in serious off-camber situations in my Grand Cherokee, and have driven on the Autobahn in Germany. NONE of it compares to the PUCKER factor I experienced while towing my tractor with the Grand Cherokee.
I would NOT recommend to anyone to exceed the rated towing capacity of your vehicle in that manner!
However, one of my buddies is a test driver for Chrysler and I know they regularly drive with loads that exceed the tow rating of a vehicle and do all sorts of tests on transmissions, brakes, vehicle stability, etc.... The ratings the auto makers put on vehicles is prudent and usually a tad conservative.
Is exceeding the tow limit by 900 pounds legal.... Technically I guess you could get in to trouble with local authorities, but I'd be highly surprised if anyone paid attention to you unless you were driving crazy.
Is it safe to exceed the tow limit by 900 pounds in your case? Personally I wouldn't worry too much. Just make sure you are careful... Properly strapped down, weight distributed on the trailer property, a WD hitch, etc.. If you normally look 500 feet ahead of you for trouble/when to stop, I'd be looking 1000 ft ahead....
</flame suit off>
Now I tow my tractor with a GMC 2500HD with the D/A and I don't worry about trailering NEARLY as much!