How to Change Transmission and Differential Fluid on the WRX

DIY video showing you how to change the transmission and rear diff fluid in your 2015-2021 WRX. To purchase fluids for your next oil change visit our website:
www.subispeed....
Subaru 75W90 High Performance Gear Oil:
www.subispeed....
Dimple Magnetic Manual Transmission Drain Plug:
www.subispeed....
Motul 1L Transmission GEAR 300 Gear Oil 75W90:
www.subispeed....
Motul 2L Transmission 90 PA GL-4 / GL-5 Gear Oil:
www.subispeed....
Redline MT-90 75W90 GL-4 High Performance Gear Oil:
www.subispeed....
Red Line SuperLight ShockProof Gear Oil (1 Quart):
www.subispeed....
Subaru WRX Manual Trans Drain Plug Gasket:
tinyurl.com/42...
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[@destinfurloughray1592]

A good tip is to always loosen you’re fill plug bfore the drain plug just so you know you can actually fill it back up after draining

[@coreturkoane5570]

absolutely!

[@hongseokkim9289]

for 2020 wrx owners, Subaru changed both drug and fill plugs go on the rear diff. transmission into H10(drain) & 17mm(fill). fyi, both relocated from back side to passenger side.

[@bluesboytyler]

And they used this new one on the 2022+ wrx as well

[@aredd92]

I have done this a couple of times on my wrx and it’s important to know that fluids like Motul come in liters which is slightly more than a quart. This is good though as 3 liters has always been the perfect amount for me, even when I made sure that the transmission fluid was warm and let it drain for an hour. Also note that the factory fill trans fluid is a synthetic blend 75w-80 gl5 manufactured by Mitasu of Japan(difficult to get). Motul 300 is a great fluid, but it is a bit thicker in viscosity so it just doesn’t shift quite as well as the factory fluid in the cold/during warmup.

[@K03sport]

75w(winter) is 75(w)inter in both. The 2nd number should be the operating temp weight. Is this why ppl choose the redline fluids?

[@aredd92]

@@K03sport That may be the case, but the sae rating system really only describes the two extremes of the spectrum. One is at 0 degrees F (W) and the other at “operating temp” (around 212 degrees F). This doesn’t accurately describe the change in viscosity with respect to temp in-between those two extremes, this is what Viscosity Index is supposed to describe. When looking at the technical data of the oil manufacturers it’s evident that the factory fill is a good bit thinner throughout its useable temp range. This could be a pro or a con however, perhaps some are willing to sacrifice cold/warm-up drivability for added protection at hotter/operating temp.

[@aredd92]

@@Ahsangill19 That would be a mistake. Mt90 is a gl4 fluid. You need a gl5 fluid because the wrx transmission shares the sump with the front diff(hypoid gears). So it needs the additional extreme pressure additives that a gl5 fluid has. But that gl5 fluid must ALSO be designed for manual transmissions so that it is “compatible” with the synchro materials. Motul 300 fits this criteria, as does Motylgear 75w-80 gl5. I’ve tried them all and the most consistent fluid other than the factory fill is Titan Sintofluid 75w80 gl5. This can also be purchased under the “Febi Bilstein” name, but it needs to be labeled “75w80 gl5”.

[@aredd92]

@@Ahsangill19 I know exactly what you mean about the tune. It’s part of the reason why I sold mine a few months back. That, in addition to the horrible warranty support and customer service by the dealers. Probably won’t ever go back to Subaru especially now that the STI is gone.

[@Kaz8693]

Are you saying to use 80 instead of the oem 90? Why not just get oem fluid from your local dealership?

[@dillpickle88881]

Glad he said remove the fill plug first, was about to instant comment make sure you can get the fill plug off before you Drain very important so you can actually re fill it 🙌🏼

[@garettbond6182]

Super helpful video to know how easy it is, I just don’t have a jack like that to lift my car off the ground that high

[@KevinVo]

We're gonna need to get Foster an apron for when he works on cars. Maybe we should do a Subispeed apron?!

[@ryanmerrill2230]

Right on Subispeed coveralls

[@K03sport]

...but they will only have 3 available and then it will be out of stock for 4 months...

[@ryankeller3159]

Yooo doing this in a couple weeks. Thanks!

[@SubiSpeed]

You got this! Just don't get fluid all over your shirt like me

[@JevaughnGraham123]

damn, this is much easier than doing the CVT transmission

[@danpluso]

Over filling would suck but you could just use the pump in reverse to pump out the excess.

[@alexs_wrex]

You'll be able to tell if you overfilled the trans because the car will fill sluggish and decelerate quicker than normal when you let off the gas. You can use a siphon hand pump to pull out oil if you overfill. Overall easy job though and yea way cheaper than going to the dealer.

[@K03sport]

Doing the change with the car level is paramount. A diy home garage change would require the car on 4 jack stands or the fancy quick lift jacks...

[@TWRX18]

yesssss so glad for this i plan tro do this in the next month or two

[@SubiSpeed]

your WRX will be happy you did

[@VentureOnMedia]

Great video man! Do Rotors next! 🤙🏻

[@SubiSpeed]

Appreciate it, we will try and make that happen for you!

[@alexs_wrex]

@@SubiSpeed yea, would like to hear what pad/rotor combo you guys recommend

[@jamesli5116]

Thanks Subispeed, definitely do it when I hit 60k maintenance. Dealer charge $960 with this and spar plugs replacement

[@codyc5762]

Snap on tools aint cheap!!!

[@K03sport]

@@codyc5762...and labor is more than likely approaching $120-140/hr for standard brands and $200/hr on lux brands...

[@joestasi8329]

Thanks! Good video

[@Takeiteasy376]

DONT DO THE 3.5 QUARTS. I did…it was too much…I then tried to pump fluid out, and the plastic straw on the pump fell in my transmission…8 hours later, I finally got it out. Haha

[@curtomaru8077]

Dork haha

[@K03sport]

...at least you got it out.

[@davidd_bmxx7967]

how much quarts then? 3qts?

[@charlielaughrey1655]

My 2022 WRX took 2.9 liters.

[@luisorozco8583]

I love your vids🥰

[@bradgreen987]

DIY only way to go. Gear oil, however is nasty stuff. Spilled some on passenger floorboard, took 3 months for smell to die

[@Midwest_Tyler]

The dealership quoted me $600 to do this 🤣 I said nah, I'll do it myself.

[@nathanpuffenbarger5423]

Same!!

[@echo7mike]

I believe there are 2 gaskets/washers for the transmission drain plug. The ones I have used are black and need about 52 lb-ft. Otherwise, the fluid will drip from the plug.

[@MD-pz3cn]

LastHumansGarage had a good video on this, detailing the different washers and their associated part numbers.

[@austin702]

Where do the gaskets go? They plugs don’t have heads, is the seal at the bottom of the threads?

[@pokerlovr0493]

do you have link for exact gasket you use

[@Drunken_Immortal]

Love the vid not hating at all but man is it a completely different beast doing this without a lift 💀

[@jamesmota]

Needed this!!

[@bradgreen987]

Anti seize on front and back imperative

[@Cheeseypoofs85]

disclaimer: ALWAYS break loose the fill plug before draining the fluid. you dont wanna have a seized or cross threaded fill plug with no fluid in there

[@j168vlogs]

wtf, who is this guy?? lol. I’m just playing, nice way to change things up

[@K03sport]

Why does Subaru have to be different spec'ing the 75w-80 vs the more widely popular/available 75w-90?. Sometimes I think automakers go out of their way to force you to go back and visit their parts counter. Could you have gone the Redline route as well?

[@zackstaa7826]

Emissions and drivability. Slightly better fuel economy. Smoother shifting, stronger engine braking, and transmission warms up faster with thinner fluid. At least that’s the theory. In the manual, Subaru says using anything other than Extra MT Fluid will decrease fuel economy and drivability. 75w-90 is fine as long as it’s gl5

[@driznitheraliznoodra]

Love these videos bc they're so concise and brief. Can you do a clutch fluid change?

[@jairoaguilar3838]

Super helpful

[@robertmontgomery7158]

My brief experience is GL5 fluid for differential and GL4 for manual transmission. I know in my Mazda RX 8 manual I can use either GL4 or GL5. Not sure if this applies to Subaru manual

[@WRX_THUNDER]

You know the front differential and transmission share the same gear oil and fluid reservoir.

[@eAmores]

Do one for the sti

[@tiaelliott6651]

Something I don’t understand is…. Does the transmission and diff use the Same oil?

[@Beatcheeks89]

Yes

[@Subieboi91]

Can you do transmission video for CVT please. Mines a 2015.

[@itsrasta1645]

Why do other forums and videos say the front is torqued at 51 not 32 like this video? Which one is it?

[@NalZero]

Not sure if you have one, but one for the STI would be nice unless the process is similar for it.

[@SubiSpeed]

Process should be very similar, STI is actually a bit easier since there is a fill plug on the underside of the trans

[@artmakary4555]

Can you show 2021 wrx differential fluid change? It’s a bit different.

[@alesana4546]

Don't want to make assumptions but owning my first wrx here got me confused on this. I take it the diff use the same oil as the transmission?

[@p791205]

Do I need to replace the gasket? Need to prepare a few?

[@DIMILifts]

Going to be purchasing a 16wrx with 150k km (95,000 miles approximately) too late to replace both diffs and tranny fluid?

[@omgbeatz7039]

Can’t find a clear answer for this but can I use the motul 75W90 for both the trans and rear differential on 20 WRX

[@12347Shadow]

I have a 20 as well, and there isn't a lot of information out there on it. What I discovered is the rear diff is actually different. I have the FSM and the fill and drain port are on the side of the diff rather than the back on the 20, and both have a gasket that should be replaced. Motul Gear 300 would be correct for the rear diff, however, the transmission takes a GL5 75W 80 fluid. This isn't easy to find, but Motul actually sells another one with this exact rating called Motylgear. You can still use Motul Gear 300 in the transmission, but the Manual states that you sacrifice some driveability with a GL5 75W 90 fluid. If you live in a hot climate like I do, you can probably get away with it, but I'm still going to use Motylgear in mine since it's the same viscosity as the factory fluid.

[@joezeigler]

what’s the front lip you guys have on the car in the video by chance?

[@aland7236]

Today I learned that an MT WRX has a transmission dipstick. Could we avoid using the transfer pump to fill the trans if we have a really long funnel, or is there too much stuff in the way when mostly stock?

[@KevinVo]

You can use a funnel. Depending on what kind of funnel you use, you may need to remove the TMIC.

[@Lando83M]

I used a funnel with a clear hose attached to it, nice and easy

[@SubiSpeed]

Yup this can easily be done with a funnel as well!

[@K03sport]

Does that mean you would use a fluid extractor to remove the old fluid? Sounds like you want to do the fluid change with wheels on the ground...

[@MD-pz3cn]

​@@K03sportNah, you can just get the car level on four jackstands and do both the trans and rear diff from there. Drain the trans from the drain plug and refill from the dipstick tube.

[@maverick2242]

What hand pump and where did you get that for your 1 quart bottles cheers

[@JayKururugi]

What's the process for doing the CVT? I'll submit my car to learn the process

[@PROV96]

Where can i get this manual pump that screw on bottle? Thank you!

[@jongotti4007]

Can you run redline mt90 in a 15 Sti?

[@SubiSpeed]

Sure can!

[@Austeno96]

Is there a transmission filter that needs to be changed when doing this too? Have a 2015 wrx 6 speed manual just wondering seems like no one changes a filter but when I Google it they show filters foe 2015wrx??

[@Silenced4Ghost]

There should be no filter for a manual , it’s probably for the cvt wrx

[@Diegofa20]

Can someone please let me know where this lip is from?

[@christosam6283]

Does anyone know the subaru part number for the transmission drain plug gasket? The link isn’t working

[@santiagoarce448]

You can probably call your local Subaru dealer and order one from them. I think that’s what I will end up doing. Should be cheap.

[@blk41010]

You said you would leave a drain plug gasket part number... your link no longer works @subispeed

[@isaacbastian8401]

Damn, I wish I could have an entire shop and lift for a brand new modified wrx. That shits expensive

[@intox69]

Tired of the dealer rippin me off lol, thanks.

[@stefanponzo538]

Anyone who didn’t realize Subaru switched the rear diff from the r160 to the r167

[@jorgea279]

Yall confused me with all those links

[@stefanponzo538]

20+ wrx has a different rear diff

[@ronschunck6574]

You don't use a torque wrench as a ratchet!

[@K03sport]

...you are also supposed to exercise them in both directions at max setting 3x - 6x prior to use for a consistent reading...but I never see anyone do that. It isn't haard to make an exercise bench for the torque wrench, but some stout hardware and a solid surface are in order

[@MouseCIick]

I don’t have a lift.

[@K03sport]

4 jack stands will work to ensure the car is level and give you enough room to work

[@codyc5762]

You forgot to tell people to go through gears with car running as transmission fluid flows through the ports causing you to top off nearly half a quart of transmission fluid! Also if you dont go through gears after transmission flush you will most of time not go in gear.

[@K03sport]

...in a manual transmission? Where are these ports located?

[@codyc5762]

@@K03sport within the transmission there are small ports for fluid to flow through to all the gears and input shaft

[@octavioguzman2836]

So I’m doing my transmission fluid on my wrx cvt do I need to program it dealership told me I need to ??