I am attempting to determine the maximum trailer weight that anyone has towed with a 98 Expedition 4.6 ltr all stock.
I know what the book says, I am looking for real world data.
AND what sort of issues did you have?

 

Due to the age, mileage and engine/suspension package your truck has I woud start with a couple thousand pounds less than the book specifies and see how it does. Just because the book says something, that don't make it so for a 14 year old truck.

 

Issues, you mean like hard to stop, hard to steer, can't pull a hill and losing control? Overloading doesn't get you anything in the end except maybe lawsuits.

 

My Mamma told me mamny years ago if I didn't have anything constructive to contribute to a conversation to keep my mouth or in this my fingers shut!

 

This commentary sounds completely constructive to me.

 

The things I listed are the things that can potentially happen when you are over loaded. Seems constructive to me. You are expecting someone to come back and say "oh yes I towed 11,007 pounds and everything was fine". I can guarantee you it wasn't fine, and if someone did then they got away lucky. Your truck was designed to stop when loaded to specs. Try going down a big hill overloaded and wait for the rotors to warp, turn cherry red and potentially not be able to stop. Try going up and blowing the tranny. Your truck was designed to steer when loaded to specs. Try to maneuver with too much tail weight (either on the tongue or the trailer or both) and good luck keeping it on the road. God forbid you have to swerve. Your tires are rated for the load your vehicle was designed for. The list goes on and on - cooling system, motor, suspension - all of that was designed 14 years ago to handle a certain load safely. As Moto Mel suggested you are likely below that threshold now.

 

Posting a question on an internet forum will always get the poster a lot of differing answers. Many of which the poster may not want to hear, but that is what you will get in a public forum. Alwaysfords41 is amost always right on with his comments and I think you may have mis-interpreted what he said and taken it the wrong way. He is right in his comment and if you are in the great state of Texas you have had to feel some strong winds while driving out there, I know I have. It would be bad enough to lose control of your rig and have an accident because it was overloaded, but to get sued and lose on top of it would be very unpleasant.

 

My '00 Expy is rated at #7500 and has the 265HP 5.4 engine.
Your 4.6 engine has a lot less horsepower/torque and your transmission may be the older model too.

I have regularly towed a 26' TT that can weigh 5500lbs when loaded.
Frankly, I would not attempt more if many major hills were involved on my routes. As it is, on the long uphill grades I poke along at 40-45mph.

For some reason Ford did not think it a good idea to give these big vehicles engines with a lot of torque compared to their listed towing capacity.
Otherwise, the frame and brakes seem adequate, but these rigs are getting old...

Anything is possible with a short trip on level ground though.

 

Hold on folks, I am aware of overloading and all the issues associated with it.
I have been towing with various vehicles for the past 50 years.
I also have a towing vehicle specifically set up for heavy towing.
It is an F350 9200 GVW with an FI 460 and a C6, big heavy, strong and capable. The only issue it has is the 3 speed automatic never has the correct gear available.
I mostly tow farm equipment which tends to be small and heavy, cross winds have little effect on this type of load except on the towing vehicle. A properly loaded trailer with that load tracks rock solid.
Also the trailer I use is a flatbed equipment trailer with electric brakes.
Rated at 10,000# BUT it would never be loaded anywhere near that behind the Expedition if it was ever there.

I have never thought of a Ford F150 as anything more than a passenger car with a box on the back, so I am after some insight as to how well, the 4 coil spring suspended, 8.8" rear end, 2 wd F150 with a light duty passenger car transmission, and factory towing package, with an engine that blows spark plugs and eats timing chains, named Expedition, actually works out in real life. Also concerned about marginal cooling.


By the way, you do not require a zillion HP to tow something. More HP just allows you to have more speed so you can get into more trouble with the load.
Best towing vehicle I ever had was an International Travelal 4X4 that was powered by a 304 CI engine producing 175 HP. Set up with correct gears, and brakes it was capable of towing to its rated capacity without any issues. No, it was not fast but you do not need fast with a trailer.

 

I pull a small travel trailer (24') that weighs in around 4500# with our '03 5.4 Expe. It seems pretty content to cruise along at 60mph and I let the speed scrub off on up-grades. I've not tackled any serious hills yet but expect it to be pretty slow going. I'm just about to roll over 100K mi and have been towing about a year. We've used it for several cross-country trips but most of its miles are from serving as a grocery-getter. Has been super reliable and we will both be sad when she's put out to pasture (although I'm sure someone will pick it up and crank on many more miles).
From my limited experience I don't think I'd want to pull anything over 6k#.

 

While I don't have the 4.6l engine I have towed a 8500 trailer with my rebadged Expedition (Lincoln) all completely stock. Mines does have a little more hp with the 4 valve engine but as far as I know the rest of the drivetrain is the same except I have the idependent rear instead of solid rear axle. It towed it adequately during the hot summer days on relatively flat ground for about 600 miles so far. It isn't a HD truck but like I said it did the job with no problems. My previous TV's were Excursion V-10, E350 V-10 and Suburban 2500 7.4L so I am comparing to them.