differential maintenance - Subaru Outback - Subaru Outback Forums
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post #1 of 8 (permalink) Old 01-05-2011, 04:44 PM Thread Starter
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differential maintenance

The dealer says the front and rear differentials of my '09 3.0 R Premium OB need to be "flushed" every 30K. Is this legit and if so what does a differential flush consist of? I thought as long as the fluid levels were right the car was good to go.

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post #2 of 8 (permalink) Old 01-05-2011, 06:04 PM
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The flushing is just changing out the fluid. It is similar to changing the oil in the front, and a bit of a pain in the back. A "flush" usually implies flowing fluid through to get rid of all of the old fluid. This is not required. It is just a drain and fill. They both drain from drain bolts on the bottom of the differentials. The front fills through the dip stick on the side of the transmission labeled "diff". The rear is filled through a filler bolt above the drain bolt. 30k sounds right to me if you are anal about maintenance.

Search for the how-to's and you'll find some good tips.

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post #3 of 8 (permalink) Old 01-05-2011, 06:31 PM
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30 to 50k is about an average service interval if you aren't having extreme conditions.

You can find a Do It Yourself for both the front and rear diffs here on this site's DIY section. They are for the 2nd gen Outback, but your 3rd gen should not be all that different.

Have you tried using the Google search bar at the top of the forum?

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post #4 of 8 (permalink) Old 01-14-2011, 05:20 PM
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Very easy to do yourself. In either case you may want to run a good synthetic gear oil. I have run Mobil 1 75/90 in my 01 since new with 160k of smooth operation. I also run it in the 09 3.0R. The dealer is not flushing anything, like others have said it is a drain and fill. Very easy job with minimum tools. I change differential fluid every 25K.

Wow, look at the time....gotta run to catch Glen Beck at 5.
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post #5 of 8 (permalink) Old 10-05-2011, 07:09 PM
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? re the drain and fill plugs on the rear diff of your 09 3.0, are these on the side of diff?
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post #6 of 8 (permalink) Old 10-05-2011, 07:50 PM
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3.0 liter OB in 2008 has the VA-2 type rear differential. Drain and fill plugs are on the side. Not sure if it's the same in 09, but probably is.
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post #7 of 8 (permalink) Old 03-13-2012, 09:50 PM
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Flush or not to flush

My girlfriend also just got advice from dealer to change both differentials fluid. 2011 3.6R with 28k. I'm a believer in looking at the maintenance manual which doesn't seem to jive. She was also told to get an alignment -- I see no wear patterns on her tires. Comments?
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post #8 of 8 (permalink) Old 03-13-2012, 09:53 PM
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While we're on the topic, how bad is it if the rear diff whines faintly when under light throttle at certain speeds? I've changed the gear oil and it didn't get better or worse. It's been doing this for 10k and hasn't gotten any worse.

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