Freightliner Cascadia 2018 Shimmy - Help

Hello friends,

After running 500,000 - it was finally time to change all my tires. Instead of going with Michelin, I got two firestones steer tires and cheap chinese tires for the rear.

I have done literally everything. Balanced them, aligned them from Kal Tire. I’ve paid 7 hours of inspection at the dealership to find out why my front end is shaking. I’ve changed all my shocks. And yet - the truck goes all over the road at the smallest of bumps. Whether it’s with a loaded trailer or empty or bobtail - if I’m not careful, it will travel into the other lane. And I’ve also installed new stabilizer bars.

I’m now contemplating selling all these tires and getting proper Michelin tires. But before I make this decision. Is there *anything* you think I could still ask my mechanic to check? King pin, all of that stuff is fine too.

This all started after I got the steers changed from Michelin to Firestones. Should I just get the steer tires changed and test it out? Or should I take all of them off and get Michelin all around? Any tip, anything you can think of, please feel free to make your suggestions.

Thank you

 

Vibration in steering wheel at 45 mph to 55. Lessens after that. Bumpy ride. Constantly having to keep vehicle straight. Ride feels very unstable. It’s the worst on uneven roads. Changing lanes is the worst. It’s like the wheels have a mind of their own.

 

Update: tires changed to Michelin. Alignment done. Balance done. Still vibrating. Mechanic found two issues. One front wheel bearing had a slight play. Fixed. Now working on something yoke? transmission maybe? Says there is play there. Tightening that bolt.
Mechanic says everything else is fine. If problem still persists then take it to freightliner and get transmission diagnosed. See if it’s an internal issue.