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'08 Subaru Outback 2.5 n/a 5 speed whining noise

I have a 2008 Outback Touring 2.5 n/a 5 speed that is emitting a whining noise. It is especially pronounced in third gear when on the gas. When I’m not on the gas I do not hear it, and I only hear it with the windows rolled up and music off. I hear it a tiny bit in 1st and 2nd but not really. After third it starts to go away with higher speed, possibly due to very high pitch/road noise drowning it out. It sounds like a supercharger which would be cool if I actually had one. It’s bugging me! Any ideas? Thanks!

When was the last time the transmission gear oil was changed?



I’m not sure. I’ve only had the car for a few months. That being said, I had the clutch replaced shortly after I bought it. Do they need to drain and refill the gear oil on a clutch job? I can’t say for sure, but I think the previous owner took fairly good care of the car.



Gotcha. Maybe I should change the oil and see what happens.

if after changing/topping oil you still end up with a noise, you can try something like “XADO Revitalizant EX120 for Manual Transmission”, available on Amazon.
It helped me in similar situation after buying a used Outback with manual transmission.

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If your Outback is equipped w/ a rear differential, that could be the source of the sound too, so check the gear oil level on that too. Checking these oil levels isn’t something you want to defer.


Unless you were able to view hard copies of the car’s maintenance record, it would be best to NOT assume anything.

In addition to the possibility that the trans oil and differential oil were never changed, you should be aware that many people ignore the service requirement of changing the brake fluid every 3 years. Unless you can verify that all of these procedures have been done, you have to assume that they weren’t done, and you need to have your mechanic do them.

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when I bought my first “new” (9 years old) Subaru with 115K miles on odometer, it was so cheap I bough it on credit-card from the dealer, it was a “project vehicle” and it had a number of problems I through were of solvable nature

in around 2-3 weeks I took care about the most obvious problems I was left exactly with the issue OP describes: some whining noise, hard to detect where exactly it was coming from

front differential was OK and oil was more or less clean, but the rear differential had some black substance in place of oil, and it was low

I flushed that rear diff and filled it with oil, it improved the situation a lot, but some whining was still there, this is where I went for XADO additive and whining was gone in around 100-150 miles

just my 2 cents of the story

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Cheers for all the help, guys! I’ll be tackling this first thing monday!