Timbren SES and Ford Super Duty Trucks

[RMcNeal]

I have a 2014 Ford F350 Crew Cab SRW as my TV for our Monty. For about the last 3 years, the truck has been suffering from what is described as the "super duty hop". Essentially, at 45 mph, the truck vibrates up and down in the rear end so much that it will shake the lunch out of you. Speed up or slow down 2-3 mph and the vibration goes away. It's not the road, it feels like an out of round or very unbalanced tire, but it's not.
New Tires and wheels, new shocks, new U joints, balanced drive shaft, nothing has fixed it. According to Ford's engineers, the truck is operating "as designed". The prevailing theory is that some sort of harmonic resonance is being produced due to the C channel partially boxed frame. This kinda makes sense because AFAIK, it doesn't seem to effect the 2017 and newer fully boxed frame trucks. This goes all the way back to at least 2002 with the 6.4 and 7.3 power strokes and effects both long and short wheel base trucks. There are pages and pages on the ford forums and google, so I won't rehash it here. Suffice it to say that greater minds than mine have not figured it out.
All that to say, I put Timbrens on the truck this week to try and calm down the porpoising that happens when crossing rough, mostly concrete, overpasses and bridges. The truck never really squatted much when hooked up. Maybe about 3 inches at most. Now there is virtually no squat at all with the Monty hooked up. It should be noted that I put on the 8600 lb Timbrens and that, on my truck, they are about 1/4 inch from touching the bump stop over the axle with no load on the truck at all. Timbren recommends installing them with 1 to 1 1/2 inch gap, but even without the 1/2 inch spacer, I only have 1/4 inch gap. I read on their support site that this is OK and will not harm the Timbrens nor the truck, but I could get smaller ones if I wanted to exchange them.
The ride, unloaded, is hardly effected at all on smooth roads. On rougher roads, it seems to be "tighter" but not rough as I expected it to be. It actually feels like the truck did when it was new.
What I didn't expect is that now at 45 mph, the vibration is nearly gone. It is still there, but has been dampened dramatically. I think that it's because the Timbrens are so close to touching the axle bump stop, once the truck starts to hop, they are dampening the up and down vibration.
I'm sure I'm not the only one who has this "super duty hop" problem with my truck so I thought I would share this. While not a complete solution, it is well worth $317.00 to get the vibration dampened. After all the money I've thrown at the problem with no fix, this was an absolute delight.