Coming up on 20k on my 6 Speed WRX and i'm thinking of doing the transaxle and rear diff oil at 20k or 30k which is what the manual recommends. Subaru calls for GL-5 75W-90 for the transaxle and GL-5 75W-90 or 90 (i'm assuming they mean straight 90 weight gear oil? Not sure I even seen that before) depending on temp. I've seen people use 75W-80 for the transaxle but i'm not sure if that's a good idea or not. Anyways, what brand of oil/weigh should I be looking into?
'19 WRX Transaxle and Rear Diff Oil Options
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Any brand will serve you well. I always use Mobil 1 75W90 LS(limited slip) GL-5 'cause it always available where I shop. But I'm sure that RedLine, Amsoil and tons of other brands of synthetic gear lube will make you happy.
Redline makes the proper fluids for your WRX. https://www.redlineoil.com/75w90-ns-gl-5-gear-oil
i owned an 07' WRX I bought new for years until my wife got an Audi A4. It was a 6 speed manual and I did a stage 2 Perrin tune at 60K. I sold the WRX at 136K.
NASIOC use to have a herd mentality on fluids back in the day. There was a member who mixed a bunch of different gear oil he had laying around and created
"Uncle Scotty's cocktail", which I thought was stupid.
I used Valvoline Synpower Synthetic 75W90 in the rear diff from it's first gear oil change. In the 6 speed transaxle, I used Supertech Semi-Synthetic 75W90 gear oil.
That particular Supertech fluid was a but of an oddball gear oil stating not for use in limited slip diffs. As such, that Supertech gear oil provided excellent shifting characteristics
because many gear oils are too slippery and make for bad synchro performance.
I recommend Redline 75W90NS GL-5 for your transaxle. Make sure you put in the NS version
https://www.redlineoil.com/75w90-ns-gl-5-gear-oil
i owned an 07' WRX I bought new for years until my wife got an Audi A4. It was a 6 speed manual and I did a stage 2 Perrin tune at 60K. I sold the WRX at 136K.
NASIOC use to have a herd mentality on fluids back in the day. There was a member who mixed a bunch of different gear oil he had laying around and created
"Uncle Scotty's cocktail", which I thought was stupid.
I used Valvoline Synpower Synthetic 75W90 in the rear diff from it's first gear oil change. In the 6 speed transaxle, I used Supertech Semi-Synthetic 75W90 gear oil.
That particular Supertech fluid was a but of an oddball gear oil stating not for use in limited slip diffs. As such, that Supertech gear oil provided excellent shifting characteristics
because many gear oils are too slippery and make for bad synchro performance.
I recommend Redline 75W90NS GL-5 for your transaxle. Make sure you put in the NS version
https://www.redlineoil.com/75w90-ns-gl-5-gear-oil
I've changed both these fluids on my WRX and to date have 99K on the clock and have used OEM 75W-90 GL-5. No problems to date. As mentioned above there are so many gear oil options take your pick long as it meets the required spec.
I would agree with skyactiv, the 75W90NS was the best by a slim margin, basically only because of slightly easier engagement when really cold. Since you're in PA, that's what I would recommend. For the front and rear diffs, I personally use Motul Gear 300 in every Subaru I own and service. It's a great fluid.
My 15 wrx called for those to be changed at 30k miles which is what I did and it was pretty easy, good youtube videos out there show a few tricks. I bought the Motul 75w90 that everyone raved about online, didn't seem any different in shifting afterwards or anything else not sure I see the added benefit but if you sleep better so be it. The real savings is in the labor of doing it yourself if you can.
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XCID, I said the Motul was not quite as good as the Redline 75W90NS in the trans... shifting is a little stiffer with the Motul in cold weather. But in the diffs, the stout add pack and insanely high VI (200+ IIRC) seem to deliver great results.
Amsoil Severe Gear is another solid choice.
Amsoil Severe Gear is another solid choice.
Lots of good info in this thread, I miss my old car where I put whatever the cheapest oil was when it was due to be changed and didn't worry about it. So just to be clear, we are talking Red Line 75W90NS for the front transaxle and Motul Gear 300 75W90 for the rear end, do I have that right? And XCIDMigs I always do my own maintenance, I didn't even use the dealerships free oil change coupons.
OP, yes, you won't go wrong using the Redline in manual transaxle and Motul in the rear, and also Motul in the front if you ever own a Subaru with a non-manual trans.
As I also said, if you already have an Amsoil Preferrec Customer account, by all means use Severe Gear interchangeably with the Motul... it's good stuff too!
As I also said, if you already have an Amsoil Preferrec Customer account, by all means use Severe Gear interchangeably with the Motul... it's good stuff too!
I do not have any type of Amsoil account, i'm just a dude in my garage obsessing over oil on a car I could run super tech in and not notice a difference haha. I'll probably wait till 30k but I rack up miles fast so i'm gonna order now so I have it when it's time.
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