Hey, I purchased a 2006 outback last year. It now has 71000 miles on it. About two weeks ago it started to shutter mainly at higher RPMs. Seems like it's between 3rd and 4th gear. Any ideas what this would be?
Does the speed of the car make a difference in the shudder? Temperature a factor?
Flush the transmission. It may help. Sounds like the 3rd or 4th clutch is going or it could be a sticking valve or solenoid. If you catch it early enough and its a sticking valve or solenoid, it may correct it before it damages the clutches too much.
With mine, the adaptive shifting programmed in the TCM was covering up a problem with 3rd clutch until it was too late. Had to rebuild it again after 17k miles.
You may consider removing the pan for inspection and cleaning the sump screen.