differential Fluid
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15k if your driving is "severe." I think it's only "inspect" otherwise, so when it's needed. I just did it at my thirty month service, at about 19k miles.
I'd say a decent guide for normal folks would be 6 years or 60,000 miles. I think the schedule just says I for inspect. Really? how would you do that in the rear diff? just stick a finger in and see if oil is on it?
operation in the southwest, towing, racing, etc. would also be considered severe duty by many people - as would infrequent and short trips.
but really, a lot cars go to 150-200k and no one has changed that fluid. There's no combustion products in it, but, if you really use your soob on dirt, gravel roads and bad weather - where other cars would fear to venture out - then I think 30K or even 15 is not unreasonable. There is a vent and normal heating/cooling cycles will pull in a little dust and moisture over time. If you EVER ford deep water, you may need to swap the fluid asap as the cooling effect/pressure differential could pull water into the diff.
operation in the southwest, towing, racing, etc. would also be considered severe duty by many people - as would infrequent and short trips.
but really, a lot cars go to 150-200k and no one has changed that fluid. There's no combustion products in it, but, if you really use your soob on dirt, gravel roads and bad weather - where other cars would fear to venture out - then I think 30K or even 15 is not unreasonable. There is a vent and normal heating/cooling cycles will pull in a little dust and moisture over time. If you EVER ford deep water, you may need to swap the fluid asap as the cooling effect/pressure differential could pull water into the diff.
That's what the service manual says you do to inspect it.
Same with the front.
what if there were a cup of water in the bottom or a chunk of metal on the magnet? Unlikely sure but, If I were gonna go the trouble to remove the top plug, may as well just pull and clean the bottom one and swap out the fluid.
but that's me.
I don't disagree necessarily, but that is what the service manuals says you do to inspect and check the level.
I did them myself. I did the front one evening, and the rear the next morning, about 2-3 hours total, including clean up. That time will be cut in half next time. For my 2010 I needed three washers, two for the rear drain and fill plugs, and one for the front drain plug. Front is filled through the dipstick. I bought Subaru Extra S from Fred Beans, which was pricey, 3 quarts for about $40 shipped. I barely dipped into the third quart. You need a drain pan, obviously, a long funnel to fill the front and some sort of pump to fill the rear. I used a suction gun to fill: This one, to be exact. It worked great!
Drain washer part numbers:
Rear differential gasket x2 803918060
Front Differential gasket 803926090
Transmission gasket 11126AA050
The rear drain plug magnet had a sizable dome of gunk stuck to it. I'm glad I did it when I did.
this guy appears to be draining and removing his? anyway, this is a Forester, some diffs could look a little different. Lowest plug is drain. BUT, best advice is to remove the top, fill plug, first. Then remove the bottom one - prepared to catch the stinky oil, then, clean the magnet on the bottom one off, then reinstall (the book says uses a selant, I think some folks get away with nothing, I used teflon pipe tape which NO ONE recommends lol!) then, fill with new fluid until it begine to overflow out the fill hole. I used one of these to fill;
Front diff: 30-60K
Rear diff: initial at 3K then every 30-60K thereafter*
Having changed enough rear diff fluids in our Subaru family, the rear diff fluid is usually quite dark with a LOT of metal after the initial breakin in my experience. Once you change that out, it usually stays nice and honey colored for a long, long time assuming you're not doing anything extreme with the car.
As mentioned, ALWAYS remove the fill plug first. Nothing worse than draining then realizing you have a stuck fill plug.
I just use the large side of a 3/4" drive on a breaker bar and they both came out with ease on my 2012. Front diff is a bit different, need I believe the T-70 torx bit (luckily have plenty from my VW days), and then you fill it through the vent tube (at least on the 2.5)
I've always used Redline 75W-90 with great experiences. Also, I've always used blue loctite on the threads and have never had an issue removing them.
and remember...75W-90 STINKS like death, be VARY careful
Rear diff: initial at 3K then every 30-60K thereafter*
Having changed enough rear diff fluids in our Subaru family, the rear diff fluid is usually quite dark with a LOT of metal after the initial breakin in my experience. Once you change that out, it usually stays nice and honey colored for a long, long time assuming you're not doing anything extreme with the car.
As mentioned, ALWAYS remove the fill plug first. Nothing worse than draining then realizing you have a stuck fill plug.
I just use the large side of a 3/4" drive on a breaker bar and they both came out with ease on my 2012. Front diff is a bit different, need I believe the T-70 torx bit (luckily have plenty from my VW days), and then you fill it through the vent tube (at least on the 2.5)
I've always used Redline 75W-90 with great experiences. Also, I've always used blue loctite on the threads and have never had an issue removing them.
and remember...75W-90 STINKS like death, be VARY careful
One or both of these plugs require to replace the OEM seal/crush washers as well, if and when you check and/or replace the fluid...... .. I had it done at Subaru dealer and that is, what they have done (and charged for)....replaced crush washers, that is....
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