Strangest thing. With the weather worsening, I put the top on the runner and wa-lah, the shudder B gone! The new rancho springs aren't so springy, and the shocks aren't so stiff. It feels like a new truck because the front end is now stable and the thing doesn't shake like hell when I hit a bump. What happened? Mark

 

Weight...
I was going to suggest putting a few hundred pounds back there, but someone beat me to it

 

But is it weight or stiffening of the truck body? I had a couple of people back there with one in passenger seat and it still shook when the top was off. Mark

 

I bet it's a combo of the two, but more of the latter with the roof.

Somehow with it on, it ties the rig and stiffenes it to make it not shudder.

Kind of like you see some leave their tailgates down on trucks and then the area back there is not stiff anymore and you can flex the two sides easier.

I wonder if Todd had this happen when he's run with his top off.
Corey