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CVT Fluids: A Consolidated Thread
Hello r/subaru,
We've been seeing a big influx of questions about CVT fluids lately,
with an average of 1-2 threads per day for about the past month. So,
I've decided to make one consolidated thread about it. Future question
posts about CVT fluid will be deferred to this thread. In response, I
want to get as much information as possible into a single place, so
users like yourself can make as informed of a choice as possible.
------
#What is a CVT?
Let's start with the basics here. The Continuously-Variable
Transmission, or CVT, does not work the same way as a "conventional"
automatic transmission which you may have been used to previously. So
let's start our journey with a conventional auto trans.
In an automatic transmission, there are a series of planetary gearsets.
These gearsets will be surrounded by a number of hydraulically-actuated
clutches. The hydraulic fluid inside of the clutches are controlled by
the transmission computer, through a mechanism of valves that are
controlled by solenoids. The solenoids and valves all exist in a
component known as a "valve body." As the TCM commands certain valves to
open or close, different clutches will be engaged which subsequently
will control elements of the planetary gearsets. This is how your
conventional automatic transmission achieves changing gear ratios.
In a CVT, by contrast, the gear ratio mechanism is a set of cone-shaped
sheaves or "variators" with a belt (or in Subaru's case, chain) run
between them. Instead of the valve body controlling clutch packs, it
instead varies the fluid pressure inside of both sheaves, such that the
cone surfaces can get closer together or further apart. Because the
thickness of the chain doesn't change, by opening the sheaves, the chain
will ride down lower into the cone shapes, thus being on a smaller
diameter. Because the chain doesn't change length either, there needs to
be a corresponding change to the opposite change to get closer together
to make the chain ride on a larger-diameter part of the sheave. Thus,
the transmission computer achieves different gearing ratios by adjusting
the gap of both sheaves in tandem. If you're having trouble visualizing
this, [here is a good
animation](https://www.youtube.com/watch?v=PEq5_b4LWNY) explaining the
motion.
Before someone interjects, yes there are clutch sets inside of a CVT as
well. Specifically in a Subaru transmission, there are 3 relevant ones;
there is a planetary set inside the powerflow for your Drive or Reverse
functionality; there is a Lock-Up clutch inside the torque converter,
and in most cases there is a Multi-Plate Transfer clutch for your all-
wheel drive "center differential" function. These functions are more-or-
less identical to their equivalent components in a conventional
automatic transmission.
#OK but what about the fluid?
There are quite a few differences between CVT fluid and conventional
ATF. Part of these differences are how the fluid is used in the
transmission, and part of the difference is because of what the
transmission does to the fluid.
In a conventional transmission, you have many clutch packs actuating
whenever the car is changing gear ratios. Just like in a manual
transmission clutch, or like your brake pads, every time there is slip
between the clutch material and the friction surface, a little bit of
that clutch material will wear off. In a conventional transmission, this
means that over time, that clutch material will begin to accumulate in
the fluid, which gives it a burnt smell and a brown tinge. By contrast,
a CVT does not use as many clutches inside of it, and as such, clutch
material contamination is drastically reduced inside of the CVT fluid.
Another main difference has to do with the fluid pressure inside of the
transmission. While a conventional auto only needs fluid pressures
around 150-250 PSI to operate the clutch packs, a CVT requires much
higher line pressures of 650-850 PSI in order to keep enough "squeeze"
force on the sheaves to hold the chain. The CVT fluid also functions as
a friction modifier between the chain and sheave, wherein it helps the
chain "grip" on the otherwise-smooth pulley surface. Because of this,
CVT fluid is very specific about its chemical properties and should not
be substituted for any other fluids.
#So... should I service the fluid?
Let's start this by looking back at what a conventional automatic
transmission requirement would be. [Here is the service manual schedule
from a 2010 Forester.](https://imgur.com/o15NYKr) I've highlighted ATF
for you, but basically it only says "Inspect [and replace as necessary]
every 30k miles." Okay, but what does it mean by Inspect? The service
manual has [this inspection procedure](https://imgur.com/ndrdp6T) for
checking the level. It also has [this condition
table](https://imgur.com/ZTk88cO) listed for what to do when you find a
condition-based failure. I've highlighted the "thick and varnish"
section because this would be the clutch wear condition I described
above. *Generally speaking,* your average Subaru 4EAT or 5EAT will have
noticeable signs of discoloration every ~60k miles.
So what does Subaru say about CVT fluid then? Well for comparison, let's
look at a 2018 Forester service manual. [Here is the service
schedule,](https://imgur.com/dC5EmY2) which you can see has an
identical "Inspect [and replace as necessary]" every 30k miles. As for
an inspection process, it only offers [this inspection
procedure](https://imgur.com/pC3RDem) and [the same condition
table](https://imgur.com/WN4EyoS) as before.
Because the schedule and condition checks are basically the same for
both service manuals, it would be very easy to assume the fluids needs
the same replacement schedule -- and I strongly suspect this is the
driving force behind so many CVT fluid recommendations. However, if we
read this again, remember that we only need to address the fluid *if if
fails one of the condition checks*, and that the most common failure
condition in a conventional automatic transmission largely no longer
happens in a CVT. It is because of this that your Owner's Manual
probably describes the transmission fluid as a "lifetime fluid."
#What about what other countries say?
A claim I very often see made in threads about CVT fluid is that
"Country XYZ requires fluid changes every X miles!" I want to nip this
in the bud now, because it's not true. Now because I work in the US, I
cannot access foreign service manuals, but I can get ahold of owner's
manuals, so here are a few examples:
[here's a UK 2018 forester owner's manual](https://imgur.com/xkJgOkz)
([link](https://subarucore.s3.eu-west-2.amazonaws.com/wp-
content/uploads/2020/06/12140046/Forester-2018-Owners-manual-1.pdf))
[Here's a n Australian 2020 forester/XV
schedule.](https://imgur.com/iFkSian) Subaru Australiia [has .pdf copies
here of warranty booklets.](https://www.subaru.com.au/owners/warranty).
[here's a Japan 2018 forester's owner's
manual](https://imgur.com/dgpDL2P) ([link](https://www.subaru.jp/afterse
rvice/tnst/forester/pdf/A8230JJ-G.pdf?downLoaditemRadio=&downLoaditemRad
io=pdf%2FA8230JJ-G.pdf)) and it says in the bottom row there: 交換時期 |
無交換 which translates as Replacement time | No replacement
Here is a 2020 WRX owner's manual from Japan, straight off Subaru.jp:
https://www.subaru.jp/afterservice/tnst/wrx/pdf/A1760JJ-A.pdf
[pg. 465 is the service information for transmission/differential/etc
gear oils.](https://imgur.com/hwlL95X) The 3rd section is for CVT fluid:
>トランスミッション フルード
> 使用オイル スバルハイトルクCVTフルード リニアトロニック用
> 規定量 約12.4L
>交換時期 無交換
Translated:
>Transmission Fluid
>Used oil Subaru high torque CVT fluid for Lineartronic
>Prescribed amount about 12.4L
>[**Replacement time No replacement**](https://imgur.com/e8162c1)
The only subaru branch AFAIK that [does list a required CVT fluid
interval](https://imgur.com/OMfHvgm) is Canada, ([soruce](https://www.su
baru.ca/WebPage.aspx?WebSiteID=282&WebPageID=18541)) where if I'm being
honest the way it's written in their maintenance guide makes it seem
like they just never changed it from ATF-era cars, where Canada also
listed replacement as necessary every 100k km. (It only refers to
"transmission oil" and does not specifically mention CVT fluid, but
everywhere else differentiates the two. It also does not differentiate
manual vs. automatic transmission fluid, like everyone else does.)
There, it's listed as a 100k km service item.
#that didn't answer the question though.
You're right, I didn't. The long answer is that you should have your
fluid inspected by a technician familiar with Subaru CVTs, and if deemed
necessary, you should replace the fluid with genuine Subaru fluid as
required by your particular model. If following the conventional wisdom
from ATF-era cars also makes you feel more comfortable, then defer to
Canada's schedule and plan to perform a fluid service at your 100k km
(60k miles) service.
#A quick note about "Severe Usage Schedule"
Another common discussion point I see brought up is the Severe Usage
schedule. I largely blame the confusion for this on Subaru, who have
written this in a hard-to-understand way in the owner's manuals.
However, a 2010-2014 Legacy/Outback service manual [has the best
representation of the severe usage shceudle.](https://imgur.com/lJHNnJk)
As you can see, the only time Severe applies to your CVTF is if you
"repeatedly tow" with the vehicle. This guidance has not changed with
newer cars, however the new way it's written [is confusing to
read.](https://imgur.com/Sc4o1lw) (CVT fluid is maintenance item 12;
see above where it shows this as Note 4.)
#A last quick note on Differential Fluid
Just want to quickly touch on this one. Your Subaru has separate,
distinct fluid for the front differential. While you can see from the
above service schedule that the guidance for its fluid is functionally
the same, differential oil gets contaminated in a completely different
way. Because a differential is basically all metal-on-metal wear of gear
teeth, especially after break-in your fluid will get dark and metallic
very rapidly. This is normal. [Here's my personal Crosstrek at 19k
miles.](https://youtu.be/etBBiMih10I) **In my own personal experience,**
I would recommend replacing your gear oils at 30k miles, but the fluid
condition will stay good for longer after the initial change, such that
it can go every 60k thereafter.
#On fluid changes and failures.
I just want to quick touch on ways that we see CVT failures at the
dealer and how it relates to fluid. By far the most common issue we'll
run across, is from the "small" CVT, the TR580, which is paired with any
of the 2.0L or 2.5L naturally-aspirated engines. Typically somewhere in
the 100-150k mile range, a failure in the valve body, usually for the
Torque Converter Lockup Duty solenoid, is relatively common. This is a
failure in the electronics side of the solenoid, and thus has no
relation to the CVT fluid; as such, changing or not changing the fluid
has no real bearing on the likelihood of this failure occuring. The
second issue we see, the most terminal one, is called Chain Slip. [Here,
at 0:23, is a fantastic example of severe chain
slip.](https://www.youtube.com/watch?v=uyYbt1Zt1H0) Chain Slip can
develop from a variety of causes, but generally is the result of a lack
of fluid pressure squeezing the sheaves against the chain; when this
happens, the chain essentially does a burnout on the sheaves. This
leaves a wear groove in the sheave face, and makes chain slip much more
likely to occur whenever the same gear ratio is used. There are some
conditions of fluid degradation that can increase the risk of slip;
these largely result from fluid overheating, which degrades the
additives that help provide friction between the sheaves and chain.
-------
Hopefully there is enough info in here for you to decide for yourself if
or when you would like to change your fluid. Feel free to post your
questions or anecdotes below. Thanks! :)
########################################################################
|u/Dannyz - 3 months
|
|Thanks for this resource. What are the symptoms of a solenoid failure
|vs slip failure?
|u/Chippy569 - 3 months
|
|Good question! For solenoid failures in the valve body, typically
|you'll get a flashing AT TEMP light along with other related lights.
|Usually a code scanner would indicate a P2764 or P2763 depending on
|exactly which way it failed. Owners tend to not report noticing any
|change in driving, however without an applied lock-up clutch you'd
|get worse gas mileage and higher trans temps. Chain slip often will
|feel like a "hard shift" or "harsh shift" in a conventional automatic
|transmission. Sometimes you'll get a squeal or squeak type noise
|followed by a shock -- the squeal is the chain slipping and the shock
|is it catching again -- usually gets worse as it gets hot. Note that
|for owners of Ascents or new leg/out XTs, the squeak noise heard when
|shifting into or out of D/R when cold is normal behavior -- this is
|actually the forward/reverse clutch slipping slightly and doesn't
|indicate a problem.
|u/Dannyz - 3 months
|
|Shit. So feeling like it’s dog walking going up hill seems more
|likely chain slip than solenoid? My 14 XT with 80k miles is making
|me mightyyy nervous. No codes or lights yet…
|u/Chippy569 - 3 months
|
|high-load low-RPM problems can be engine instead of trans --
|would recommend diagnosis if it's bothering you.
|u/Dannyz - 3 months
|
|Thank you. Local dealership can’t replicate, no mountains near
|them. Service manager keeps trying to sell me a new Subaru with
|the fear of the cvt going, but his department can’t find
|anything to give a diagnosis. Makes it hard to tell if he is
|being sincere and trying to help, vs up selling. While driving
|at highway speeds, on the highway, as the grade gets steeper,
|the car will feel like it’s walking instead of driving
|smoothing. The steeper the grade, the worse it gets. I it more
|in medium to high rpm with higher load. I’m not towing anything
|and only have two people in the car, so it’s not a crazy load.
|I don’t see it at speeds below ~40mph Edit: thank you again
|u/icecon - 3 months
|
|We own a 2020 CPO Ascent and while it works it has two possibly
|transmission related quirks that I have been unable to figure out.
|1) When going uphill, say at 35mph, if we ease off the gas - the
|RPMs actually spike upwards! I'm assuming this is the computer
|"downshifting" way overaggressively but it's highly irrational when
|the driver is easing simply wanting to decrease speed. Only by
|letting go of the gas entirely is this prevented. Any fix? 2)
|This is one is more recent, but on drive the car seems to enter
|"engine braking" mode at times at slowish speeds on flat terrain,
|where it shows that no combustion is taking place (i.e. it reads
|99.9 mpg) and the vehicle starts slowing down mildly, there is a
|soft clacking noise when this happens and also when engine brake is
|applied manually. Thoughts?
|u/rippel_effect - 3 months
|
|Very thorough breakdown, thanks for taking the time. In my opinion,
|as well as other master techs that I've worked with, it's a good idea
|to drain/fill your CVT fluid around 75-80k miles. I did my 2017 Outback
|2.5i at 74k and sent it out to Blackstone, it came back with zero
|issues. What are your opinions on a drain/fill as a preventative
|service?
|u/Chippy569 - 3 months
|
|> What are your opinions on a drain/fill as a preventative service?
|I don't see strong enough of a correlation for doing or not doing a
|service and having or not having future problems. My opinion is do it
|if it helps you sleep at night and your wallet can stomach it, but
|your car isn't going to explode if you don't, lol.
|u/pilotdog68 - 1 day
|
|You seem to know what you're talking about, but you're one of very
|few to say it doesn't matter. Any idea why so many disagree? As a
|casual, I can understand they idea that the fluid doesn't break
|down, but it seems like a good idea to periodically drain out any
|suspended particles from the components wearing.
|u/Chippy569 - 23 hours
|
|>Any idea why so many disagree? ~~Oldhead~~ conventional wisdom
|and historical norms, primarily. Same reason some people are
|doing oil changes at 3k miles on cars that don't need it. The
|point is there are *far less* particulates in a CVT than a
|comparable conventional auto trans
|u/JulieTortitoPurrito - 1 month
|
|single drain/fill or double?
|u/rando_commenter - 3 months
|
|Much appreciation, clarity but with nuance is a wonderful thing the
|internet.
|u/Dutchboy347 - 3 months
|
|I'm at 143k miles on my 2019 crosstrek. I never changed the cvt fluid.
|Would anyone say I should bother it? I'm getting shuddering when at 1k
|rpm traffic buildup I notice it more and more.
|u/Sweaty-Taste608 - 3 months
|
|Thanks for putting this together. I recently did a drain and fill for
|the first time at 130k miles. I notice a significant improvement in how
|smooth the transmission shifts now. Previously, I would notice lag at
|times, and symptoms similar to what you described as chain slip. Those
|are gone. So, I’m happy that I did it.
|u/abunnyrabbit - 3 months
|
|Excellent write up as usual.
|u/wafflesbananahammock - 3 months
|
|Great info, thanks for putting all that together. I've been wondering
|if I should get my CVt fluid changed on a '17 XT with 55k miles. The
|dealer didn't recommend it but ended up giving me a $400 service
|estimate. I had a leaking transmission pan gasket they replaced a
|year ago - how much fluid would have been lost for that? The service
|records didn't indicate replacement fluid.
|u/Chippy569 - 3 months
|
|>The service records didn't indicate replacement fluid. it would
|have to be, removing the pan also drops most of the fluid.
|u/wafflesbananahammock - 3 months
|
|Excellent, that's what I was hoping for. Surely they wouldn't have
|captured the old fluid and reused it right? I'm hoping that
|transmission gasket replacement was basically a CVT fluid change
|for me as well.
|u/Chippy569 - 3 months
|
|> Surely they wouldn't have captured the old fluid and reused it
|right? I suppose it's technically possible, but I've never heard
|of a shop wasting the time and tools to do so.
|u/Fiveaxisguy - 3 months
|
|Thank you for this. Great writeup. I just had my '23 Outback
|Wilderness CVT fluid changed at 23k miles because I was trying to be
|super cautious. Looks like I can wait a while for the next one!
|u/Bruce_Wayne8887 - 2 months
|
|23k seems insanely cautious.
|u/Fiveaxisguy - 2 months
|
|Indeed, it is. I admit to freaking out a bit about the CVT in
|these vehicles. But I've done it now, and likely won't do it again
|for another 40 or 50k. It eased my mind, and I already had the skid
|plates off to change the differential fluid...
|u/Bruce_Wayne8887 - 2 months
|
|No worries. After watching the MrSubaru video on cvt fluid, part
|of me thinks Subaru shys away from a replacement fluid schedule
|is due to the CVT being so sensitive to contaminants.
|u/Cozmo85 - 1 month
|
|On my 2010 I did a drain and fill at 100k and a drain and fill at
|270k when my valve body solenoid went out lol.
|u/Riley_Cubs - 3 months
|
|148k in my 2016 Legacy, CVT fluid has never been changed to my
|knowledge.... Is it going to explode?
|u/kindofcuttlefish - 3 months
|
|Amazing work u/chippy569, thanks for putting this all together! Was
|planning on defaulting to the 60k interval but this t[hread on
|mountainous driving & engine braking](https://www.reddit.com/r/subaru/c
|omments/1deij74/am_i_straining_my_cvt_by_using_my_paddles_to_not/) has
|me wondering if I should do it sooner. Would you recommend drivers
|living in the mountains who use the ACC or paddles for engine braking
|to exchange the CVT fluid more frequently? If so, how much more
|regularly? Seeing recommendations in that thread saying as often as
|every 20k but that seems excessive. Some info about my situation: I
|don't mess with the paddles but regularly use cruise control to keep
|speed in check when going down 7% grade CO mountain passes on the
|interstate. I don't tow anything. 2022 2.5 NA with TR580
|u/Chippy569 - 3 months
|
|I live at the exact opposite of a mountain, so I don't have much
|experience to pull from here -- what do your local dealer(s) say
|about it? -- but the "severe schedule" interval for towing is 40k km
|or ~25k miles, so you can follow that as a guide for the most extreme
|end. Just as a guess since you aren't towing, double the severe
|schedule would be a good rough idea.
|u/Chippy569 - 3 months
|
|The filling procedure needs to be done with the car running in Park
|at a specific temperature (~100°F), without a scan tool that can read
|ATF temp it's very hard to know what temp the fluid is at, so it's
|easy to set the level wrong. I think "mrsubaru" on YouTube has a
|video on the procedure for a DIYer
|u/Impressive-Bison8862 - 23 days
|
|Couldn't you just lift the car so it's level-- making sure the
|engine is cold. Then catch and measure the amount of fluid coming
|out of the CVT. Replace the fluid with the exact amount you
|removed. No need to wait for the CVT to reach 100F. It's just a 1
|for 1 replacement. Can I assume that's an OK way for a DIY'er to
|do it?
|u/Chippy569 - 23 days
|
|You could try to, but you'll need to figure out how to fill a
|fluid higher than the fill hole.
|u/Impressive-Bison8862 - 22 days
|
|Thank you for your quick response! BTW, Love reading your
|posts and replies. So refreshing to hear from someone who has
|actual hands on experience!!!
|u/ExpressProfessor1632 - 2 months
|
|Kudos Chippy569! Are we wrong? Trying to maintain our vehicle, but
|where did we go wrong? We need assistance with our 21 Ascent. Bought
|it as a CPO purchase May '23 and it had 56k miles on it. Since the
|transmission maintenance is suggested at 60K, I am assuming this would
|have been a part of the CPO 152-point inspection. Please correct me if
|I am wrong. We have had the oil changed three times between Oct '23
|and May '24. Trying to stay on top of the maintenance as a good Subaru
|owner. The car started making a vibration as if you were driving over
|rumble strips when turning about 6 weeks ago. So we found an
|independent Subie Shop owner (ASE certified) to run a diagnostic test
|and some other maintenance items, such as the alignment, and they
|suggested a drain and flush. No diagnostic error codes before any of
|their work, but after the drain and flush it threw error codes. They
|have documented that the trans fluid was not low coming into their shop
|and was not low leaving their shop on a tow truck unfortunately to a
|dealer. The dealer receives the car and says it is 4 quarts low on
|transmission fluid so the warranty is voided. End of story and 10K,
|please. Fork it over. Oh, I need to mention it now has 96K miles, with
|a CPO 100K powertrain warranty. Very close to the 100K limit, so no
|need to honor this warranty I suppose. Now we have a claim with SoA
|and like so many complaints over the web, SoA is not a customer
|advocate; they do not at all meet this definition. We cannot get
|returned phone calls. The car has been gone 3 weeks, some people have
|it worse than this. They aren't even considering our maintenance
|documentation and were told it did not matter. We do not believe the
|car was low on fluid. At this point I believe they are being dishonest,
|told the agent kindly that it was boiling down to our word against
|their word and they stated, "We will only go by what the dealer tells
|us." So that's a dealer advocate, not a customer advocate. We're
|still waiting for a phone call that should have come last night by EOB
|and today is already gone. Error report from the dealer:
|Transmission - Automatic: Inspected found multiple codes, P0867
|Transmission fluid pressure, and P0747 Pressure control solenoid A
|stuck on. Inspected and found fluid 4qts low. Filled transmission and
|test drove the car. Transmission is operating, transfer clutches
|chatter on tight turns, and transmission is harsh during upshifts,
|recommend transmission. Since the transmission is operating, can we
|drive it to a different dealer? or don't drive at all?
|u/Chippy569 - 2 months
|
|> I am assuming this would have been a part of the CPO 152-point
|inspection. Please correct me if I am wrong. Subaru does not have a
|service requirement/recommendation at any mileage, so no I would
|definitely not assume a CVTF service would be included with your CPO
|inspection. Some dealerships may choose to do so; you'd need to look
|at your paperwork from then. >The car started making a vibration as
|if you were driving over rumble strips when turning about 6 weeks
|ago. This would most likely be transfer clutch judder, which can be
|a side-effect of other issues, or can be its own independent issue.
|>They have documented that the trans fluid was not low coming into
|their shop and was not low leaving their shop on a tow truck
|unfortunately to a dealer. This really throws a big wrench in
|coverage -- once someone else touches it, there's a pretty big he-
|said-she-said, and subaru will default to taking the dealer's word
|over a third party shop. >The dealer receives the car and says it is
|4 quarts low on transmission fluid so the warranty is voided. If it
|really is 4 qt low, then yes, that would be warranty-voiding. It
|would be relatively easy to determine this, simply perform the fill
|procedure and see how much fluid it takes to get it refilled
|correctly. In this case, the finger would be pointed at the previous
|shop, who likely did not perform the fill procedure correctly.
|>Inspected found multiple codes, P0867 Transmission fluid pressure,
|and P0747 Pressure control solenoid A stuck on. These would both
|indicate that the low fluid finding is more likely accurate than not.
|>, transfer clutches chatter on tight turns, and transmission is
|harsh during upshifts, recommend transmission. and this would imply
|there is some amount of chain slip occurring. >Since the
|transmission is operating, can we drive it to a different dealer? or
|don't drive at all? You could try, but the case is already open, and
|now you'd be adding a 3rd party to the equation, which makes it even
|messier, and you're probably not going to get a different response.
|u/ExpressProfessor1632 - 2 months
|
|Thank you much!
|u/___cats___ - 3 months
|
|Ok, let's say, asking for a friend, their CVT failed on their '16
|Outback due to the lockup solenoid and it was replaced under the
|extended warranty, but the installation of the remanned transmission
|caused a leak somewhere around the rear of the trans and put off taking
|it back well beyond a reasonable time in which the dealership would
|give me the time of day to fix it under any kind of parts or
|workmanship warranty. I'm more experienced with cars than your
|average human...I mean my friend is..., but CVTs are foreign. Is
|topping it off something to even consider as a DIY, or just pay for a
|drain and fill once a year or so? No way I'm paying for it to get
|removed and re-sealed, it's almost 10 years old with well over 100k
|miles and is going off to college next year.
|u/Chippy569 - 3 months
|
|you might refer to MrSubaru's video about replacing a valve body in a
|TR580.
|u/___cats___ - 3 months
|
|Actually just came across it and am watching it right now. I mean
|my friend is.
|u/___cats___ - 3 months
|
|Tail housing. That's what he called it. That's where it's leaking.
|u/Chippy569 - 3 months
|
|there's no way a valve body replacement led to a tailhouse leak
|u/___cats___ - 3 months
|
|They replaced the whole transmission. Does that change your
|assessment?
|u/Chippy569 - 3 months
|
|a weird response for a valve body issue, but ok. If it's
|leaking it should be warrantable under 1 year parts warranty.
|How bad of a leak is it?
|u/___cats___ - 3 months
|
|Yeah, we're talking 3 years, 30k miles ago for the repair.
|Leaky enough that there's spots where I long-term park, but
|not enough that I've actively seen a drip while under it.
|Once my son gets home from work I'll get under it and
|verify my memory.
|u/Chippy569 - 3 months
|
|if it's just sweating a little, you're measuring that
|amount of fluid loss in like... drops. Would probably be
|fine to just ignore it tbh
|u/rippel_effect - 3 months
|
|Was it the output shaft seal on the reman that was leaking? That
|could have been damaged during installation. Or was it where the
|housing meets the case, about 8-12" forward? Either way, that's
|an issue with the reman itself, independent of the failed valve
|body in the original.
|u/radicalindependence - 3 months
|
|Concerning the fluid overheating, Google tells me that with CVTs we
|should check the air intake and outake regularly to ensure proper
|airflow to prolong the life of the CVT. What are they referring too, I
|assume it's not the engine. Also, it was mentioned to never have the
|car running when not moving due to causing more heat. Is this a thing?
|I use my vehicle (2024 Outback 2.5) for work, put on 45K per year and
|often take conference calls when stopped but the car running to stay
|cool/warm. Lots of driving but most of the miles are highway. With a
|few short trips from site to site.
|u/Chippy569 - 3 months
|
|> What are they referring too, I assume it's not the engine.
|literally never heard of that, but there is an air pressure vent on
|top of the transmission. Looks kind of like a little plastic bell,
|center of the trans, underneath the air intake duct. >Also, it was
|mentioned to never have the car running when not moving due to
|causing more heat. Is this a thing? not to any real significant
|amount, but yes the car being in park means the torque converter is
|in full shear; the torque converter is the biggest source of heat for
|the trans fluid. Additionally, not moving means no airflow, which
|means less ability to dissipate the heat.
|u/GoBSAGo - 3 months
|
|I’m weary of the long term reliability of the cvt in my wrx. What are
|the failures you’re seeing in the TR690 and what type of care do you
|recommend for someone who does a lot of around town driving as well as
|occasional mountain road blasts?
|u/Chippy569 - 3 months
|
|> What are the failures you’re seeing in the TR690 Behind the torque
|converter, there is a chain that transfers power from the torque
|converter to the oil pump for the trans. That chain has a little
|cover plate. Seen quite a bit of them leaking, depending on the year.
|See [TSB 16-103-16R](https://static.nhtsa.gov/odi/tsbs/2019/MC-101644
|46-0001.pdf) for more info.
|u/GoBSAGo - 3 months
|
|Yeah, mine’s leaked from the cvt pan, that oil pump, and then the
|rtv gasket that connects to the front diff. Any other trans failure
|points to watch out for?
|u/Chippy569 - 3 months
|
|nah that's pretty much it, tbh. Your WRX CVT uses the cool VTD
|center diff previously found on the 5EATs, pretty unique setup.
|u/GoBSAGo - 3 months
|
|Haha! First I’ve heard anyone say the cvt in my wrx had
|anything cool about it. Thanks for the reply.
|u/Chippy569 - 3 months
|
|The sensor is up in the valve body. Not sure how accurate pan surface
|temp vs internal temp would actually be. I'm sure it could be mathed
|out, but I doubt it's 1:1 An IR temp ilgun isn't going to accurately
|read a thin fluid stream coming out of a check plug.
|u/Cozmo85 - 1 month
|
|One of the cheap blue Bluetooth readers on Amazon can read fluid
|temps
|u/Elegant_Draw_5619 - 2 months
|
|This is excellent! Thanks so much!
|u/adamsalami30 - 2 months
|
|Thanks for the great write up. If you don't mind me asking, I'm
|planning on replacing the torque converter for my friend's 2012 legacy
|with 100k. How risky do you think the operation would be (I've heard
|that even with a new part taking apart the transmission causes issues),
|and what's the likelihood that the CVT fluid would need to be topped
|off afterwards?
|u/Chippy569 - 2 months
|
|Not risky at all if you know what you're doing, just use the
|new/updated OE part. It will need a slight top off.
|u/UncleGurm - 1 month
|
|What's your take on the "SPT" version of the WRX CVT? Conventional
|wisdom over in r/wrx_vb is that we're all looking to change it at a
|reasonable interval just due to the fact that we all drive like ... uh
|... assholes. But that's based solely on the "we're abusing this"
|presumption and/or paranoia, not any hard facts.
|u/Chippy569 - 1 month
|
|The "spt" is the trans guts from the ascent but with the VTD center
|diff from a 5EAT. Not dissimilar to the prior VA WRX trans, just an
|iterative update.
|u/dannyryry - 1 month
|
|I went lifetime with my Nissan Altima cvt and it went 240000+ miles. I
|am so uncertain about this in my xv, but this is an amazing write up
|thank you.
|u/mkArtak - 1 month
|
|As many have mentioned already, this is a great writeup - thank you!
|My dad has a 2018 Forester Premium, which is now at 123.000 miles. CVT
|fluid has never been chnaged, so I was thinking that it's worth doing
|it. Unfortunately, we're talking about a country, where there is
|practically no any kind of Subaru presence - no dealerships, no "subaru
|experts". I am familiar with the flush & drain procedure, and have all
|the tools to service it myself, but the issue is that the original
|CVTF-II fluid isn't available in this country. Nor the Idemitsu SB2
|alternative. I've looked around and found many other brands of oils,
|like Motul, Mitasu, ... . Given this limitation, which brand of CVT
|fluid you'd recommend me to go with?
|u/stinkypoopoo93 - 14 days
|
|Hey /u/Chippy569 ! I just posted a thread here, but just saw this
|pinned - maybe you can offer advice for me. I brought my car to Mavis
|2 days ago for a simple inspection and oil change (I usually only ever
|go through the dealer but was tight on time this week). I got a call
|about an hour after the car was dropped off that the guy doing my car
|accidentally drained my transmission fluid. They refilled it and did my
|oil free of charge, but I feel really uneasy about it and have zero
|confidence that they may have even used the right fluid. I also am
|fairly certain my transmission fluid was flushed/refilled when I
|brought my car in for the 60k service. My question is - if you were
|in my shoes would you go to Subaru and have them reflush the
|transmission fluid? I've had this car for 5 years now and have never
|had an issue. I'm willing to pay for this to get re-done the right way
|with OEM fluids cause I want my car to last. Any thoughts or advice
|appreciated!
|u/Chippy569 - 14 days
|
|First things first, I would check your receipt and verify it mentions
|the damage, and then see if it lists a part number for the fluid
|used. If not Subaru fluid, yeah I'd personally want to get the
|correct stuff put in.
|u/stinkypoopoo93 - 13 days
|
|Just confirmed with Mavis it was Valvoline CVT fluid. I'm assuming
|that's good enough for now since it is at least CVT fluid to drive
|about another 20 miles before I can have Subaru reflush and fill
|back up with OEM fluid, right?
|u/Chippy569 - 13 days
|
|Yeah
|u/NothingButACasual - 12 days
|
|I have read the center diff is "sealed", but is it really? Or can that
|fluid be drained and replaced?
|u/Chippy569 - 12 days
|
|In a CVT, the center diff fluid is also the trans fluid.
|u/NothingButACasual - 12 days
|
|I thought so but couldn't find anything on it! So if you had to
|run an undersized spare for a short drive in an emergency, would it
|be beneficial to have the CVT fluid changed afterwards in case it
|had overheated?
|u/Chippy569 - 12 days
|
|Depends on what we mean by "short drive" but probably unnecessary
|u/NothingButACasual - 12 days
|
|Fair. Thanks for responding and actually answering! Lots of
|technicians just get snarky at dumb questions so I appreciate
|it
|u/toomasjoamets - 3 months
|
|Here in north-eastern Europe there is no requirement or recommendation
|to exchange the fluid. The dealer doesn’t do it unless customer
|requests it and even then they recommend doing it at a company who
|repairs all kinds of automatic transmissions and they have developed
|their patented method of doing a “dynamic fluid exchange” to cycle the
|whole fluid for transmissions that haven’t by design a possibility to
|change the fluid. Usually people do it at 100 000km, but is it actually
|useful is a matter of debate. We have here a rather cold climate and
|transmission overheating issues are not common among regular drivers. I
|know one guy who did the dynamic exchange at 100k and the company said
|that the fluid actually was in an ideal condition.
|u/Chippy569 - 3 months
|
|>developed their patented method of doing a “dynamic fluid exchange”
|this is just a flush machine. Basically they remove the coolant
|in/out hoses and insert their machine into it. The transmission
|naturally pushes fluid out; the machine pumps fresh fluid in the
|return. It's debatable whether these are truly a safe idea or not.
|u/toomasjoamets - 3 months
|
|What do you think about it? Safe or not and why?
|u/Chippy569 - 3 months
|
|I'm more inclined to do drain-and-fill services, similar to an
|engine oil change.
|u/toomasjoamets - 3 months
|
|Even if you only exchange the fluid partially? Considering that
|regular drain will not remove all the fluid?
|u/Chippy569 - 3 months
|
|yes.
|u/toomasjoamets - 3 months
|
|Cool. Thanks for your opinion. Thumbs up.
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