A bad shake has developed in my relatives 2008 Chevy HHR SS. I can replicate it by getting up to highway speeds and letting off throttle. Certainly feels like its coming from the front passenger. We have replaced a CV axle to try and fix the issue. After installation it seemed to help a bit but the noise and vibration were still there. Some time has passed since the new cv axle was installed and its gotten worse. The only way to have a somewhat smooth ride on the highway is to constantly have some load on the drivetrain.

Any help is greatly appreciated!

 

to the forums!

The link in my signature may be of some help.

 

Welcome to the site, the lower control arm rear bushings could be worn out, or the ball joints . ZZP offers LCA’s either new correct ball joints and FE5 rear bushings.
https://zzperformance.com/products/z...m-control-arms

 

Thanks! Couldn't find my particular issue. Much appreciated!

 

Thanks for the suggestions! I'll check bushings and ball joint. Ill report back my findings.

 

Could be bad engine/ transmission mounts.

 

Look thru the oblong hole in the passenger side wheel well, if the bolt head is low in that hole you have a bad upper engine mount.

 

My experiences with other makes models is the engine / transmission mounts are worth looking at.
Especially if the shake can't be isolated to one side of the vehicle.

 

My similar problem was caused by bad LCA rear bushings.

 

Thanks @Oldblue for the suggestion to check the rear bushings on the LCA. The rear was indeed shot. New bushing installed and now we are smooth at highway speeds. Thanks everyone else for the help and suggestions!