You state the transmission fluid was changed. Clarify whether this was fluid or oil (yes, there’s a difference) and exactly what was used?
Trans fluid/oil change, noise in the center front, etc. can sound suspiciously like a final drive noise.
Subaru for whatever reason just does not make decent wheel bearings in their vehicles. They fail earlier than latter typically.
The sound you describe sure sounds like a wheel bearing failure. I would hope for that vs the other potential problems in the drivetrain.
You may want to get the differentials oil changed out for good measure also and see if it goes away. There is no maintenance related to your center differential.
Good luck.
Thanks everyone.
Transmission fluid is what was changed. I don’t know what type, I will find out.
Until I get this figured out, I guess I have only one last question. Should I be driving it at this point?
I would hate to recommend driving it without knowing what oil is in the transmission.
Driving, coasting in gear/neutral, pavement or grass surface, or whatever means the ring and pinion gears are rotating.
From your post I gather this noise is somewhat of a whine and one thing you do not want to do is wipe out a ring/pinion gear. This will be xxxx dollars to fix.
Is the fluid in there thin and red or…?
Did this noise appear right after the fluid change?
Well, I’m going to borrow a truck for a few days, just to be safe.
The color of the fluid is the same as it was before I did the change. It is sort of a clear and oil, maybe like a light olive oil color, but almost no color at all? It isn’t red.
I didn’t notice this noise right away, it has been about 2 weeks. But that doesn’t mean it wasn’t there, I’ve been known to drive with loud music.
I’ve been reading over a bunch of subaru sites, and it sounds like this is a common problem after a manual transmission fluid change - if you use the wrong stuff. So I’m going to try something else as soon as my mechanic gets back and hope it goes away. Honestly, I didn’t realize that the front differential uses the same fluid as the transmission.