TomG2 wrote:
Since everyone else is having a guess or two, here is another. What is the condition of your shock absorbers? Lots of things can contribute to this "porpoising" effect.
This where I would look!Get some really good shocks for the truck, I run Bilstien 5100's. Then look at the TT does it have shocks? If not look at spending the $$ to put them on!
I tow a 32' 5er, and have reduced this effect to almost zero.
I did truck first with the 5er in mind, the truck shocks helped a lot, but I went over an old concrete bridge on the way to the coast with this setup, and damn we got a heck of a bounce going!!! I installed shocks on both axles of the 5er, (CW kit on sale $120 an axle), about a month after the install had to drive down an old county road, chip sealed old concrete, I could feel the bumps, but didn't get the bounce. Then just last weekend had the opportunity to travel over the same bridge as before, not smooth as glass, but far, far better than without shocks on the 5er.