9900i shake/wobble

Harmonic Balancer. Engine mounts.

Remove all drive and steer tires and balance individually and replace, with Centra matics (<-----this fixed my problem), they'll look at you funny - but tell 'em you're paying the bill. Put a run out guage on each one as you do it.

Inflate drives to 110PSI, steers to 115.

Loads of grease on the 5th wheel?

Quality alignment.

That's me.

 

Yeah - it sounds stupid, but it fixed the problem for me. Myself, I went into the shop and helped them do it, observing the runout guage too. If you can find a shop that doesn't get upset about you being in there.

A couple of tires had to be busted down and turned 90-180 degrees then re seated.

I'm tempted to get the centering sleeves too. Balance beads didn't work for me - the CM did. I put them on the trailer too, just to try and address every problem. There's 160,000 on the entire set, and not quite half worn down.

 

I had a similar problem recently with vibration under load. Turned out a faulty levelling valve was dumping the drive airbags enough that the driveshafts weren't aligning properly. Replaced the valve and got the chassis height back to normal- all good.

 

GMB it was more a vibration than shaking but I could feel it through the gear stick as well as the seat. My hood shakes all the time so no difference there.