car shudders while driving at 35-40 mph

I take my vehicle to a Subaru dealer for regular oil changes, etc. I have always taken care of my vehicles.

when I explained the problem, they told me they would research it. I was told they could not make it happen when they drove the car but when I told them my "husband" knows there is a problem, they decided to look at it again. But, no problem found. In the last 2 weeks since they looked at my car, the shuddering when accelerating has gotten worse. when I called the Subaru dealership, they read what was in my file and said, they couldn't find anything wrong before. I am going to try a local auto repair shop and when I called Subaru to cancel my appointment because I needed to find another mechanic, they were just fine with it. Very unhappy with this dealership and I have been a very long time and loyal customer of theirs. I have always recommended them to others but not any more.

The car shakes real hard when driving between 40-50mph. went to the dealer, they said that the drive shaft went bad and guess what, it is not serviceable, like other normal car you just replace the U-joints and that's it, in Tribeca you have to replace the whole shaft! Man this car is a real junker. I really wish I never bought it. Please don't buy a Tribeca and as I keep saying I had to find that the hard way you don't. Stay away from this car.

Update from Jan 23, 2016: I went to the dealer again because I didn't believe it is a middle driver shaft and I showed them the TSB bulletin about the Automatic Torque Converter. They double checked and they verified the problem they quoted me $6220. Guess what finally I sold it today and I got myself a 2016 RAV4. Screw SUBARU.

I bought the car for 13300 and sold it for 8500 in 9 months I know I lost money but with all the issues I faced I consider myself a winner as I got rid of the subaru finally and for sure. NEVER EVER IN MY LIFE, I SWEAR TO GOD I AM BUYING A SUBARU EVER EVER AGAIN!! Piece of junk!!

I hope someone of the big heads in SUBARU company see this. I just want to let you know that your company SUCKS. The 9 months I owned the Tribeca was a nightmare that finally came to an end. I am happy I made this decision.

Finally I want to congratulate anyone who read my issues with the Tribeca and helped them avoid these cars. And I feel bad for anyone who bought a subaru and now started looking at these. Wish everyone a good luck!!