Right rear shimmy, 20 to 35-40 MPH, then diminishing (1 Viewer)

[Rad26rio]

Dear Mud Brain trust,

I have a pestering slight shimmy coming from my right rear (or it feels as such) at lower, around town, speeds. Seems to dissipate once highway speeds are reached. You can shift truck into neutral and shimmy remains. It makes the head rest slightly tremble and weird vibrations in a glass of water in cupholder.

2007 LC with just under 170k miles

background:

AHC replaced with OME all around, stock height (or very close) maintained.
Nitto tires replaced with Bridgestones, road forced balanced, alignment done...it “rolls” smooth as silk
steering wheel rock solid, no shimmy with it
independent shop has ruled out wheel bearings, driveshaft, drivetrain.
undercarriage does have some rust, but nothing that would denote broken frame or anything that severe.

what is left?

Rear upper or lower control arms?
misdiagnosed universal joints, rear driveshaft?

I would love to have this last hurdle overcome to make this truck ride like new. Any ideas appreciated or better yet, somebody that has solved this exact issue.... and yes, I did search forum for clues before posting, no solid smoking gun uncovered there.

Cheers to you all in these weird times....

 

[abuck99]

Read through this post- might help you narrow it down

Pulsing/droning vibration at highway speeds

This diff bushing won't cure driveline vibes. Even brand new the bushing flex's quite a bit. Replacing that may help cure a portion of the D-N-R clunk but thats about it. Driveline vibes are hard to isolate with out removing prop shafts one at a time and test driving with CDL locked. Once you...

forum.ih8mud.com