Sorry it took so long guys :-)

Don't know how to attach any larger images...

 

I believe those bars are meant to keep the bed from swaying side to side, but I can't confirm 100% from the pictures. If they mount directly to the frame in the center or at the two bushings that connect to the rear corners of the frame through rubber bushings then I can confirm it.

Dodge doesn't show this part on their drawings so I am assuming that it is part of the full bed assembly...

 

That first pic shows the cast solid bar, complete with reliefs to let the spare tire lowering tool by, held at the ends in those cups, bedded in very soft rubber. The cups are welded to the tubular bumper reinforcement, right where it bolts to the ends of the frame. If you reach up and grab the bar, it is so softly mounted, that you can probably pull/push it almost a 1/2" at the ends and rotate easily 45 degrees. Mounted to nothing else, and as you can see, is really tucked up there, out of sight.

Really strange it's not on dodge drawings...I might pass the concept by some seasoned mechanical engineers here and get their take of what it might be for as well. Whatever it is, it's higher tech than I expected to find under a pickup, lol!

 

http://www.factorychryslerparts.com/...ssembly=658519

Found it! It's called a mass damper....doesn't look like its on all models as far as I can tell....

 

Damn, I'm feeling dumber and dumber....I should have done a search..

https://dodgeforum.com/forum/2nd-gen...sues-help.html

https://dodgeforum.com/forum/3rd-gen...ss-damper.html



BTW, the last poster, Stumpbreaker, was one of the more versed guys that had 4.56 vibration problems. If you notice in his signature, 'optional exploding driveshaft' he is eluding to losing the DS at highway speed after quite a few miles with vibration...I don't think he ever solved the problem, but I remember he was very close in describing all the issues brought up by installing 4.56 gears in a 1/2T highway truck.

 

Mine's too old and I certainly didn't remember any useless weight back there when hooking up an extra 7pin plug inside the rear of the box for my trailer. Well mystery solved now

 

Pretty cool read on the dampers...

Those parts are in the parts book for 2008 a little differently:


The hitch and tow hook drawing was the only one I didn't look at.

 

Hi so this dampener... Should it be almost klunking around? It seems like the rubber is worn. Anyone replace this ? Difficulty rating?..

Thanks