When to change CVT fluid?

subaru
forester

#1

I know this is unknown territory, but I’d like some opinions.

When to change the CVT fluid? these are new and possibly have problems, so I’d like to stay proactive. I had it checked at 30k and dealer said it was OK.

Manual says never change it for normal use and every 25k for severe use. I find both extreme and am looking for a better number, say 50k?

I drive 80% highway, 20% city, about 8000 mi per year. On the east coast.


#2

PS, the definition of “severe use” is such that just about all drivers are in that mode.

Basically if you ever drive in a city, or near the coast, or on a mountain, or in the winter, you are in that category. Seems like they are keeping the definition very broad for liability reasons.


#3

Okay, You got 'er, Bill! 50k sounds good to me! Does this thing have a dipstick for the CVT? I’d just siphon or pump out as much fluid as I could periodically, measure what came out and put that much back. I do that with my cars and there’s no mess, clean-up, etcetera. I collect the old stuff right into the bottles I haul to be recycled @ WM or Advance.
CSA :palm_tree::sunglasses::palm_tree:


#4

I’d have changed it at that point anyway. Just because it isn’t dirty or visibly worn out doesn’t mean it shouldn’t be changed.


#5

I think over the years most of us have concluded that you change trans fluid at 30K intervals. I just did mine at 29K so I’m good for a while. I don’t know how a dealer could look at the fluid and see that it’s ok. The idea is to change it before it changes appearance.


#6

no dipstick.
so we have 2 votes for 30k,
2 votes for 50k,
one for never (dealer)


#7

I don’t know if the Subaru CVT is more reliable or not over the long term, go with 30k. The extra changes are cheaper than a new transmission!


#8

how does subaru fill the trans at the factory? been told on a honda to make sure the fill plug can be removed before you take out the drain plug as they like to stick. would be bad to drain the trans and not be able to fill it.


#9

+1
Even if the fluid isn’t discolored, some of its additives could be depleted, and there is no way to determine this by appearance. I haven’t yet owned a car with a CVT, but when I do finally buy one, it will have its trans fluid changed every 30k miles, just like all of my previous cars.


#10

Well yeah, I remember on my TL, that fill plug was really tight. I used 1/2" ratchet but needed an extension to reach and the extension actually torqued a little before the plug gave way. I was afraid I’d break the extension or ratchet. Plus you always need to buy the new washers.

Lots of transmissions now have neither dipsticks or fill ports on top of the trans. You have to put them on a lift and pump the fluid in. There is an access plug on the Pontiac somewhere around where the axle goes in but I’ve never been able to find it. So just another one of those things to scratch off the DIY list and have done at a shop or dealer for about $150.


#11

update:
4 votes for 30k,
2 votes for 50k,
one for never (dealer)


#12

count +1 to 30K bucket :slight_smile:

I’m replacing CVT fluid in my Nissans on 30K schedule, having drain-plug helps a lot.
OEM manual instructs to drop a return house and do in-line replacement method, but they still provide a plug down below and it gets 5.5. quarts out of 8 drained, so it’s reasonably OK if done on 30K schedule, for 50K I would probably go with full replacement, so I would get car into the shop for 100% replacement


#13

If the manual says 25K for severe use, and your driving qualifies for what they call “severe”, then 25 k intervals is the best choice. Then there’s no question you are satisfying the manufacturer’s recommendations should there ever be a warranty question.


#14

The manual says to change it if you use the vehicle to tow a trailer more than once. Not sure how to interpret that.

I had to have the valve body replaced at 58k under warranty and the ATF looked like new then.


#15

A friend of mine is a transmission guy in business for over 40 years as a reputable independent.

He says service the transmission every 30k miles (as I also recommend) and he has said that almost every transmission he has repaired or rebuilt died due to one of 2 things.

  1. Never changing the fluid often enough.
  2. Running the fluid low due to a leak.

No one can eyeball fluid and tell how good it is. As VDCdriver mentioned, it’s the additives part of it that comes into play. I was told in a transmission school many years ago that the fluid does not necessarily fail. It’s the additives that break down.


#16

30k seems to be the suggestion from what I’m finding on Subaru Forester.org but some dealers are offering to drop the pan rather than a drain&fill to completely change the fluid but with a higher labor cost (600.00 just in labor in Orange county) or $300 for the drain&fill


#17

update:
1 vote for 25k
7 votes for 30k,
2 votes for 50k,
one for never (dealer)

looks like I should get it done soon…


#18

I would imagine “drop pan” to be used if transmission was not serviced for 20 years and 200K miles, but to do that with relatively moderate mileage… WHY??!

both fluid exchange or drain&fill will be just fine, for a fraction of a cost

I can totally imagine dealers inventing an additional cash generator for them, but I would not do it unless car was neglected badly and it needs a CPR vs. normal maintenance


#19

I’d like to throw a caution out there on this one. Just for the record, I’m leaving mine alone (2014 Legacy).

With these CVT transmissions, there is a lot that go wrong with a simple fluid change. If you are going to do it, the dealer would probably be the safest place to have it done. If you have an independent shop do it, make sure they are using the correct fluid and following the correct procedures. The will need a scan tool that can monitor the ATF temperature because the fluid level has to be set a specific temperature which appears to NOT be ambient or the normal operating temperature of the ATF.


#20

yes, I know it’s complicated, I’d only have it done at a dealer. The possibility of error is why I’m putting it off as long as is prudent. The fact that the dealer doesn’t recommend a change is also a factor, ie, perhaps they are uncertain on the procedure?

To all: remember this is a CVT, mostly unknown territory.

addendum: I like the way it drives and the high MPG.