I said what I did about the AWD because I ran the office in a local transmission shop about two years. AWD vehicles are nothing but trouble. People buy them and then have no clue how to take care of them.
They are required to have the same size tires front and rear. Not just that. The factories also recommend sequential serial numbers on the tires, so that they are all four as close as possible to the exact same diameter.
The viscous coupling that connects the front and rear differentials is THAT sensitive. As little as 1/2" difference front to rear can burn up a viscous coupling. Done. Over. Toast. A lot of times, it causes a violent enough reaction that it takes the transmission out with it. Can you say $5K in repairs?
And since Subaru DID come up, they have one of the most bullcrap systems there is. The break in procedure for a rebuilt transmission and viscous coupling is basically doing doughnuts in a parking lot. Ok. No problem. Know what the service manual says? Something like "if the coupling continues to chatter after break in, remove the coupling and manually burnish the cutch plates"
While I was there we only had ONE problem child that would NOT go away. Guess what it was? A Subaru AWD.
