2005 Subaru Outback 2.5i possible drivetrain problem

I just bought my Subaru in December (ODO ~82,00) and within the past week or so it has developed this weird sound, almost a whistling mixed with an occasional grind. Now, it doesn’t really seem to be affecting my speed, acceleration, or braking, but it’s unsettling to have your new car scream at you. The sound doesn’t change when I apply gas or let off, but more so changes with the speed of the car. In other words, if I gun it, it changes pitch at about the same rate as it I were to slowly accelerate. The sound seems to be coming from somewhere central in the from of the car, pretty much between the wheels, which is why I’m suspecting it’s something to do with my drivetrain/AWD system. Has anyone ever had/dealt with a similar problem?

If you make a very tight turn at a slow speed, does the car move smoothly or does it grab? What is the tread depth on all of your tires right now? If your owner’s manual describes a procedure for temporarily disabling the AWD by inserting or removing a fuse, does the noise go away if you do that?

The suspicion here is that the car has been run with tires of unequal circumference, which on a Subaru can damage the AWD system pretty quickly.

Have the fluid level in the differentials checked. If you’re lucky, changing or adding fluid will solve the problem.

If you’re not lucky, your differential(s) is(are) ruined.

Does this car have an automatic transmission? If so, check the final drive gear oil level. This is NOT the same as the ATF fluid and there should be a short dipstick on the passenger side of the transmission.

Any oil change history right before this problem started?

Before you deem the AWD the problem, rarer unless mismatched tires used, I would guess the wheel bearings may be failing.

My rear failed on 2005 Legacy GT(turbo) at 94k but Subaru covered it under some sort of extended warranty. However I think it was only on turbo 2005 models.