Painful low frequency drone/pressure in cabin

[MongooseGA]

Is it solely road speed dependant or does your throttle input impact it all like with u-joints?

 

[LJE]

Is it solely road speed dependant or does your throttle input impact it all like with u-joints?

I *think* it's all roads speed dependant. Going to spend some time on the road in the next day or two trying to rebaseline & recharacterize it after all the 'fixes' I've done.

 

[RapidRob]

Oh, interesting - I'll take a look at those and likely order the two to knock it off the list.

Wouldn't that be a hoot, I didn't even know there was a bushing there. I'll have to look at that myself to understand what it does.

 

[curryitr]

I’m no expert on these things but is it possible that all the extra sound deadening you added is trapping the resonance in a certain part of the truck, or making it have a different frequency that is painful to humans?

 

[Zuberg]

Had to edit my earlier post as I had the bushing location wrong on the torsion bar crossmember. It looks like the 'support assy, front suspension' sits inside a frame crossmember. Appears the torsion bars and support assembly have to be removed to replace the bushings.

First pic below shows the support assembly with bushings circled.

Torsion bar adjustment below with bolt/bushing circled.