Bumping/vibration from stop

subaru
outback

#1

I hear a bumping and feel the vibration coming from below between the driver and passenger seat. It happens upon accelerating from a complete stop, but still in drive. It goes away after the car speeds up a little bit more. The car drives fine. have a 2002 subaru outback with 145,000 miles on it.


#2

What kind of transmission?


#3

automatic V6