powdersuber

I realize this is an old thread, but I came across it when searching for my problem and figured I would post an answer that solved my two vibrations. I have two H6 Subaru Outback's (2005 and 2002). Both of them had a vibration... and they seemed kind of similar, both under acceleration/torque.The 2005 would shudder/vibrate at just the bottom of the gears, especially in 2nd and 3rd. But you could feel it in all the bottoms of the gears, right after it shifts. I replaced both axles myself and it did the same thing. Took it to a transmission specialist and he said he thought it would be the rear drive shaft. He suggested to take it off and try it without it to be sure. I did so (be sure to plug the back of the transmission so fluid doesn't leak out). It still did it, and seemed amplified. I bought a second 2002 Subaru that didn't vibrate when I first bought it. I swapped the tires thinking the 2005 could have bad tires. Didn't fix the shake. I thought the last thing would be either a motor mount or transmission mount that is bad. I gave up trying to fix it myself and took it to a specialized subaru mechanic. He tried the tires with brand new tires and didn't fix. He then replaced the new axles I put on and it fixed it!! I bought cheap axles from Advanced Auto and he bought good ones from Napa. They weren't OEM axles so I might have an issue in the near future... but it fixed the 2005's vibration. So the 2002 then developed a different shake... but similar as it was only under acceleration. It was much worse and felt almost like a tire was loose. I put brand new tires on it and the vibration didn't go away. It ended up being the rear drive shaft carrier that was bad on it. Hope this helps someone diagnosing this in the future...