Rear shimmy in 345?

[Honkity Hank]

Our 345 has a slight shimmy/vibration in the rear that manifests itself around 55-60 mph. I am thinking it may need new shocks. has anyone had a similar problem and if so what was the solution. Absent any insight our approach will be. New shocks, balance wheels, new tires in that order.

Thanks

[noiva]

I have a 370 with a very similar rear axle setup and overall length. Is this a new problem? If so, I'd look at the tires first. Could be a slipped steel belt. If it's not new, perhaps the air suspension bags are going/gone. Does the 345 have air bags in the rear? Shocks are the least likely, in my opinion. I had shocks that were totally gone when I got the vehicle, but all I could tell was the ride was rather hard.

[swebster]

Honkity,
I have a 345 as well and have chased most of the vibrations out. Many other have done the same on this forum. A few additional questions if you don't mind:

Vibrations and shimmys are different things (IMHO) can you describe a little more about it? Low or high pitched? Does it change when under power, coasting or decelerating? Where along the floorplan is the approx location of the vibration? Does the coach actually move up and down or side to side?

There are a number of things to check. Tires, suspension, shocks, brakes,driveline, axle, etc. Give us some more to go on and we might be able to get you close to the root cause. In the meantime try a few searches on "driveline vibrations" or similar searches on this forum for some good background information.

[overlander63]

USUALLY a vibration between 55-60 is a tire balance problem. Does the vibration come and go regularly, or is it a constant? Worn shocks could be contributing to the problem if they have allowed the tire top hop up and down while driving, eventually wearing flat spots on the tire, which makes it worse, until it can be felt. But, like Steven said, we need more info to be able to steer you in the right direction.