2008 Subaru Tribeca vibrates at 35-55 mph

When accelerating between 35mph and 55mph experience a vibration.

Sounds like an AWD issue. Pull out your wallet.

To me, it sounds much more like a problem with the transmission’s torque converter lockup mechanism. If you haven’t changed the trans fluid at least 3 times over the past 12 years, that makes this all the more likely.

However, while an AWD problem is less likely, if the vehicle has been run with mis-matched tires, and/or if the tires haven’t been consistently rotated on schedule, then an AWD-related problem is a possibility.

What can you tell us regarding both transmission servicing and tire matching/rotation?