Strange resonance

**davrac** · 3rd December 2013, 06:22 PM

Hi all. Just wondering if anyone has had similar?

Engine rpm 2200-2500 seems most apparent when towing. An on-off resonance. Kind of a whoa whoa whoa. If you know what I mean :sly:

Seems to go away when higher or lower than this in the rpm range. Not very bad just not right. I think I have ruled out the tail shafts etc as have removed and still there.

Harmonic balancer, torque convertor.

Have relatively new eng mounts and front tail shaft. Definitely seems eng rpm related and not road speed related.

Thoughts please

Cheers. Dave.

**Yorkie** · 3rd December 2013, 06:29 PM

exhaust??

**davrac** · 3rd December 2013, 06:45 PM

If it wasn't such an on-off kind of vibration when revs at steady speed eg. 2250rpm. I would look to exhaust. Definitely seems engine related.

I previously had an exhaust mod done replacing the flex joint which fixed an exhaust vibration which was constant at around the same rpm. Was much harsher and a different feeling.

**Yorkie** · 3rd December 2013, 08:08 PM

ok, only wondered as i was getting some shocking noise through the exhaust after some trials of removed centre muffler and repair to rear section.
hoping for better result now i am back to a high flow centre and rear mufflers.

is it an auto?, maybe something in the gearbox?.

or maybe you have nerve issues in your foot and are subconsiously lifting and lowering your foot, much like a sydney-bombay cabbie.

**PhilipA** · 3rd December 2013, 08:15 PM

Not the well known 2200Rpm handbrake drum resonance described in my recent posts?
Regards Philip A

**davrac** · 3rd December 2013, 10:14 PM

Ha very good, not the cabbie effect unfortunately. Wish that was the case. I have a feeling its going to take a bit of time to figure this one.

Thanks for your replies yorkie. I will definitely check the exhaust side of thinks anyway.