Vibration in 2nd - MY11 (SH) Forester manual.

[m4mal]

Interested in opinions; vibration/shake on Forester MY11 (SH) manual. 126,000km.

Car has a vibration of motor/box that is really only obvious in 2nd gear, accelerating between 30 to 40kmh.
Shake is kind of side-to-side oscilation felt through the drivers floor/pedals when torque is applied in that gear and speed.

Not so noticeable if downhill. Engine has no sense of there being a misfire - performs smoothly in all other gears.
Vibration/shake smooths out after 40kmh. Not noticeable in other gears around that speed range, only really in 2nd.
New tyres and balanced and aligned - no change.

So, what do people think as best bet for investigation?

a) CV?
b) prop shaft joints or carrier bearing?
c) other?

Thanks.

[El_Freddo]

This is a good one m4mal!

I doubt it’s a driveshaft issue as these don’t care much about gear selection - usually. Plus the OEM driveshafts are the best items out there for CV options, and they will last a very long time - some would say the life of the vehicle when boots are replaced as needed.

My thought on the symptoms would be either an issue with the transmission, assuming it’s an auto. Or it could be a dead engine/transmission mount that does weird stuff in 2nd gear when engine harmonics are just right to upset things.

If you’ve got a GoPro or some camera similar, it could be beneficial to place the camera under the foz and go for a drive to get the issue happening, stop, move camera location and do the same again. Do this 3-5 (or more) times with different camera locations and see what you can pick up. Things to point the camera at: engine/trans mounts and driveshafts, left and right sides. Maybe something will show up on the videos.

Cheers

Bennie

[Bantum]

Sounds like a gearbox mount - check to see if they are still all there ...