Hi,
posted the other week with this, but though I'd add some more info.
Got a JDM 2000 RSK B4 4AT tiptronic.
There's an intermittent low frequency vibration that sounds / feels like it comes from towards the rear of the car, often when the auto is changing / thinking about changing gear. It doesn't stop or seem to slow the gear change. The length of the vibration seems to vary from a split second, through to what feels like nearly a full second. The noise shows up hot or cold, and is especially noticeable with around town stop/start. It hasn't corresponded with any particular speed / straight vs cornering etc. Also, the tires are all good / recently balanced and aligned etc. Handles very nice 8-)
The curious thing is that the noise hasn't ever (yet) occurred with the transmission in the tiptronic 'mode'.
One thought was that it might be an engine/gearbox mount, but it occurs with low or no load.
It's booked for a service / look-see with a reasonable Subaru crowd in a couple of days, but I was curious if anyone had any ideas.