Towing Problem

I would say it's the spring bar tension in the hitch set up. Often performed incorrectly at some dealerships.
From your explanation ,because you are towing with more than enough truck, it sounds to me that you have too much lifting by the bars.
As a quick test, you should try it for a short ride direct to the ball to test it out. See if more hitch weight cures what you are feeling.
While hooked up, too much WD lift will cause your truck tires to easily spin on gravel by increasing the transfer of more weight to the trucks front end. You need to balance your load.

AT 6500# or so, I'll bet the transporter delivered that TT to the dealer using no WD hitch .
What's happening to you now, as the TT travels over imperfect road surface it lifts up on your hitch more so and you feel it pushing you in your seated position, towards the trucks front end. If this is what you are felling, then its an easy quick fix.

Take measurements, start with a level TT. Measure the TT frame to the ground both front and rear. Now,measure the ht. of the inside of the ball mount. At approx. 20" give or take, this will be your hitch height. This is where you start, now move to the truck.
( Load the truck as you normally would to take the wheel well height measurements as well as the ball measurements.)



Use the method in this link, then road test it .
This link is a general setup that will work. You can fine tune at a later time if you find it necessary.
http://davidsrvtips.blogspot.com/2009/02/hitch-setup_2781.html

budger1719 wrote:
Florida Outdoor RV set up the hitch. The hitch is a Husky 801-1200 lbs weight limit. The camper's weight etc: Camper weight-6310, load capacity-1490 and hitch weight-780.

I have the same hitch on crew cab F250 pulling a 36 Ft. Wildwood, about 8,500 lbs. and it is super smooth. I would bet the hitch was set up wrong. I would also check to make sure the shocks are still good on the truck. The F250/350 tend to beat the bushings out of the shocks. While the shock is still good is adds to the up/down motion when traveling.

While it should not push and pull your F-350, tankers tow better completely full or completely empty. To make sure we know what you are talking about, is it a forward and backward push pull or a side to side sensation? What is the frequency, once per second, or less? Does it vary with speed? Is there any mechanical noise, like clunking etc.?

Have you driven on many different roads? For example, the highway running through my city is HORRIBLE and my trailer bucks like crazy. But on out other highways, it's fine. Just has to do with the smoothness of the road.

I wonder if you have the correct number of links in use....is your TT level when all hooked up?

Florida Outdoor RV set up the hitch. The hitch is a Husky 801-1200 lbs weight limit. The camper's weight etc: Camper weight-6310, load capacity-1490 and hitch weight-780.

The weight distribution bars may not be set correctly; usually they will dampen this motion by about 2/3 to 3/4. But you never get rid of it completely, and when you go over regular expansion joints on the highway you feel it no matter what.

First, get everything weighed per the instructions mentioned elsewhere. It take three weighing's to get it all figured out. Post the results as well as other setup information for some valuable assistance.

First,
What hitch and what weight rating are the bars?

Is this felt only when going over bumps? If so, it might be something termed porpoising. Who set up your weight distribution hitch?