Transmission (?) noise in '03 Outback

[jabarrow]

Hi all,

I bought my outback at 125k miles, and pretty much immediately did a major suspension overhaul....new bearings on all 4 wheels, new CVs on all 4, ball joints, tie rod ends, etc, etc, etc.  It's now at 157k.  It is the 2.5L 4 cylinder with a 5-speed manual tranny.

 

Now it is making a noise that I think I have ID'd as transmission.  At first the noise was intermittent, and sounded like a scraping, grinding, bearing sort of noise, which was not really all that loud, but still very noticeable as "something going wrong".  Now it is pretty much constant and has changed into a soft whirring sound that is weirdly similar to crickets at night.  Not very loud, just barely noticeable above all the rest of the noise the car makes.  The noise definitely comes from the front end of the car, but sounds the same from either left or right side, which I am assuming means that it is coming from the center, left to right.  

 

The noise occurs when the car is moving, and seems to be independent of anything other than speed.  It does not matter what gear, clutch in or out, whatever.  The only significant variation is that once the car gets really warmed up good, the sound is a little louder.

 

I checked out all the obvious stuff....wheel bearings, CVs, etc.  No obvious problems.  I took it to my local mechanic, he found no obvious problems.  So, I'm thinking transmission, maybe the rear output shaft bearing?

 

So my question is, Before I go swapping trannies, is there anything else the noise could be, or does my diagnosis sound right?

 

Thanks a lot

james

[nipper]

Heat shields?

 

How old is the fluid in the transmission?

 

 

Before you start swapping major parts, lets do some more diagnoses, inspection. If it changes with speed but not with gear selection, it can be a diff that is dry, a diff bearing etc. Does it also make the sound in reverse?

[Caboobaroo]

For whatever reason, the manual transmissions in 2000-2004 Outbacks have issues. Out of all the Subaru transmissions I've replaced in the last year, 70% seem to be from that era of Outback.

 

Also note, if the noise is pretty bad, it's also likely the front snout on the driveline is eaten up, this needing it replaced as well.