I had to get four new tires for my 2003 Subaru Legacy (Sedan, automatic tranny, 112K) come inspection time this year. After the wheels were balanced, rotated and tires were mounted, I got my car back only to find that there is now a vibration at highway speed very similar to unbalanced wheel vibration. This also happens if I am straightening the wheels out after a left turn. It’s very consistent and I can feel it through the steering wheel. Took it back to the mechanic who spun the wheels and told me they were all perfectly balanced. There is an inconsistent tug to the right in the steering, so I thought it couldn’t possibly be alignment.
I’m so short on $$ that I’m hesitant to bring it in to get it fixed unless I have a really good idea of what it might be. Fire away!
Check your owners manual for installing a spare tire. It will explain how to insert/remove your AWD fuse disabling the AWD(temporarily). If this vibration goes away then you may have an issue in the AWD clutch packs or solenoid.
Also are the four tires an exact match in size/model/make/wear. If not you are likely stressing the AWD.
If there’s an issue w/ AWD solenoid etc are we looking at dreaded torque bind?
Its possible but can also be other things like a dragging brake caliper or bad shaft. The removal of fuse is a simple check for torque bind.
Thanks - looks like I have something fun to do on my lunch hour after all. 
I have heard swaping out tranny fluid a few times can help assuage the sypmtoms of torque bind, if that is what’s going on. If one doesn’t have disposable income to start throwing parts at the car, would this be a good fix? What other things can I try? Is running it with the FWD fuse on a fairly permanent basis going to damage things further?