dhare1

Hello everyone , I searched all threads several times to try and figure out this vibration that recently showed up in the motor and couldn't find much , only motor mount related things . Anyone that has an idea , I would greatly appreciate it , here's my best description of the noise: 2010 SS with automatic trans. 65K miles. All stock.

I have already replaced the top motor mount and the front and rear transmission mounts with OEM. Did not fix the problem.

The vibration starts at about 2000 RPM , it vibrates in park reved up starting at 2000 RPM, and it vibrates while driving starting at 2000 RPM. So i know it's not wheel bearing or tire related.

You can actually here the vibration and feel it in the car. The best way to describe it : it sound kind of like a bad wheel bearing at high speeds , like that WAWAWAWAWA , the higher the RPM the faster the WAWAWAWA. It's not a consistent WAAAAAAAAA.

Not a wheel bearing though , it does it in park like I said before . No codes and the motor runs fine . Any ideas guy's ?

whopper

Have you listened under the hood while someone revs it up to 2000 while in Park?

Have you checked for loose brackets under the hood, loose heat shield on convertor?

RJ_RS_SS_350

Was just thinking the same thing, sounds like some component is loose. Maybe the airbox, AC compressor, could be any of a number of things. Here are some torque specs, they're for an LSJ motor, but should be the same for nearly everything.

dhare1

Yes listened under the hood and went under the car while someone reved it up . Tightened and checked about every bolt I could find . You could feel the vibration through out the car , frame , doors , dash , steering wheel , etc. When you feel the motor it's pretty obvious. I was thinking vibration damper is bad ? I'm running out of ideas.

dhare1

I just replaced the air box rubber grommets also , I'm sure it's not that , this vibration vibrates the whole car. I'll double check bolts again .

RJ_RS_SS_350

You mean the harmonic balancer? If it's that, probably a bad idea to keep running it(not that you are). Doesn't seem too difficult to get to. There is an access panel in the passenger wheel well. There are 5 push pins and 2 small screws. You will need a 7mm or 9/32" nutdriver or socket for the screws. This tool works well on the push pins. I got it for $10 at Autozone.



You'll have to remove the serpentine belt, the crankshaft bolt, and then you can remove the crank pulley/harmonic balancer. Not sure how to tell if it's out of balance.

RJ_RS_SS_350

Haynes manual says to use a large pin spanner, or a strap wrench(with an old drive belt wrapped around the pulley for added grip) to immobilize the pulley while you remove the bolt. I'm not saying that's the problem, pretty hard to diagnose from here. You may need to tow it to a shop(or the dealer).

Hmmm... maybe the drive belt itself is bad? got some chunks missing?

dhare1

Yes , harmonic balancer . Ok , seems easy enough to get to , At least I can check to see if it's not loose. Anyone know if a bad harmonic balancer will cause this type of vibration ? Thanks for the suggestions so far , I guess it's eliminate one thing at a time . I have that tool also . I'm a good mechanic , changed out my turbo , do my brakes , Etc.

dhare1

I took off the belt and inspected , looks good so I put it back on . I don't want to take it to the Chevy Stealer !

RJ_RS_SS_350

Well next I would check all the pulleys and the tensioner. I can't imagine that harmonic balancer going bad.