would you do it ?

A 1996 Fleetwood Bounder of your vintage Had the frame rails extended by Fleetwood during construction of the coach. This was to accommodate both the addition of the tag axle as well as the extra coach length. Depending on the quality and related engineering that went into that job it would cause me to adhere closely to that 3500 Lb. weight rating.

You could beef up the added frame rails and the manner of attachment to the original Ford rails as well as installing a 5000 Lb. or more rated hitch and properly rated attachments to the re-rated
frame rail extension. My guess that anything weighing more than the weight of your present setups rating would only serve to cause you more problems in the event of a mishap than you want or need.

stepside454 wrote:
we have a 96 Fleetwood Bounder 36 ft motorhome with a tag axle on a Ford F53 Chassis. The motorhome & hitch are both rated to tow 3500 lbs.
we also have a 2009 Ford Taurus that we would like to tow behind it. the Taurus weighs 3900 lbs. so my question is, would you tow it ? an experienced buddy of mine ( who I probably shouldn't be doughting) says it wont be an issue, that its underrated .

Not even close to being an issue, but surprised you don't have a 5K lb on your rig. At any rate, it's easy enough to beef it up some and if not by you, then your local hitch install shop.
The most common problem with overloading and we're not talking about a few lbs. here, is with the transmission overheating and usually taking place, with being a ton or so over limit and arrived at, by it's rated GCWR less it's actual weight. Most everything else will handle it, upon close inspection, but the tranny won't like it and especially with the Chevy 4L80E that will tend to go into limp mode on long steep climbs in hot weather. This is a good thing for saving the day, though and one can always get 25% more towing power, by using low gear and keeping it under 25mph. That or disconnect and the latter might be wise in many instances. This you don't run across all that much from one end of the US to the other, but there are some challenges to be aware of and even if you stick to the interstates.
No matter what the case, be sure to have working toad brakes and always drive under the speed limit, which was designed for cars and even though the big rigs and the law, have never figured that out.

LIABILITY & STOPPING are the issues you need to be concerned about. Consult your ATTORNEY about these issues.

Quote:
To get additional length, the chassis was extended by welding beams onto the original framework.
It is my understanding that can be a weak spot.
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This could be a concern,....for dead hitch weight only !
It would have nothing to do w/ the weight you are putting into forward motion,.....unless maybe you had about 6,000 horse power, and floorboarded it every time you took off. 400 hp is not going to stress any welds, trust me !

Take an inexpensive, highly informative trip to a truck stop. Ideally with the RV loaded as for a trip. Have one of your crew drive the Taurus and pull both onto the CAT truck scale. Ideally the Taurus pilot gets out of the car and into the RV before the attendant triggers the scale. Only then will you know what the Taurus actually weighs and what the RV weighs. From that you can do GVWR and GCWR calculations, adjust tire pressures on the RV, and know what the Taurus weighs. All for $10.

Some of us have gone to qualified welding/fabrication/hitch shops and had reinforcing done. Sometimes the issue is that the 3500-lb hitch can be replaced with a 5000-lb hitch that spreads its mounting bolt load over a bigger footprint on the chassis rails.

stepside454 wrote:
actually , I looked again, our Taurus is an SEL. it weighs 3720 lbs., the limited weighs 3900 lbs.

you should have the vehicle weighed with whatever gas you want in the tank and with whatever stuff you want it to carry. don't forget to subtract your weight when you weigh it.

actually , I looked again, our Taurus is an SEL. it weighs 3720 lbs., the limited weighs 3900 lbs.

FWIW, I have a 96 Fleetwood Southwind, 37' tag axle on a GM chassis.
I also have the 3500 lb. tow rating.
To get additional length, the chassis was extended by welding beams onto the original framework.
It is my understanding that can be a weak spot. If excess weight is towed it could possibly break the welds.

If I was going to tow something 4000 pounds a few miles at a slow speen, I would probably just do it.
But, towing a 'overweight' toad on a normal or extended trip. I think it's just asking for problems.

I'm definitely not an expert on towing or chassis construction.
Just giving you my opinion.
Enjoy your travels.

As long as you don't over weight the hitch, (no way a towbar will) it is perfectly safe, I would do it in a heart beat.
Now if you ask about brakes, that's a whole nother story, and that's what I'm fighting right now.

Yes, I would exceed the weight ratings. In fact, I have done so, many times, with no problems.
BUT, please understand, that is just ME!
I do not recommend that YOU do it.
I also do not tell you to NOT do it.
It is a choice that YOU have to make, all on your own, and if there are any adverse consequences to your actions, YOU own them.
Good luck.