CVT Fluid: Should I Flush or Just Drain?

Hey guys, I’m about to buy a used Subaru with 32k miles, and I want to take good care of the CVT. Should I do a full CVT fluid flush or just a drain and refill? I plan to get it done soon after I buy it. Any advice?

The CVT fluid definitely needs to be changed at some point. Subaru in the U.S. doesn’t officially recommend it, but a lot of Subaru owners stick to changing it between 60k and 100k miles. For severe conditions, some even do it every 30k. I personally change mine every 30k.

BUT I’d recommend a drain and fill, not a flush. Subaru’s service manual only mentions a drain and fill, not a flush. A flush uses a machine to push fluid through, which can create issues like:

  • Fluid contamination if the machine has been used with other oils
  • Pressuring pathways that aren’t meant to handle it
  • Dislodging metal particles that could circulate through the transmission

Doing a drain and fill avoids these problems. If the fluid looks bad, you might do a few more drain and fills over a few days to clear it out.

Definitely do a drain and fill, not a flush.

Fife said:
Definitely do a drain and fill, not a flush.

Even with only 33k miles?

Baer said:

Fife said:
Definitely do a drain and fill, not a flush.

Even with only 33k miles?

I do a drain and fill every 30k miles. It’s worth it to stay on top of it.

Baer said:

Fife said:
Definitely do a drain and fill, not a flush.

Even with only 33k miles?

I did mine at 33k on my Legacy. Maybe a bit much, but I’d rather be safe, especially since I drive pretty hard.

Flushing isn’t usually recommended for CVTs. My local Subaru dealer advises against it, and we’ve got CVTs in both our cars (Outback and Insight). They recommend 60k for a CVT drain and fill.

Won’t hurt! Go for it! But I’d suggest only going to the dealer or someone who really knows Subarus.

CarEnthusiast said:
Won’t hurt! Go for it! But I’d suggest only going to the dealer or someone who really knows Subarus.

People here say NEVER to flush it and that it could cause problems, which has me stressed and confused!

@Baer
There’s so much misinformation on this. Flushing isn’t inherently bad, but it’s usually not necessary. The horror stories are often from people who waited too long and had underlying issues. If you’re already maintaining it well, a drain and fill is typically fine.

A flush can help if you do a lot of off-road or heavy driving, but it’s not a must for most people. As long as you’re changing the fluid regularly, you’re good. Don’t let the rare cases scare you.

@Axelle
Thanks! I think I’ll go for a flush now at 33k and then just do a drain and fill every 30k. Sound good?

Baer said:
@Axelle
Thanks! I think I’ll go for a flush now at 33k and then just do a drain and fill every 30k. Sound good?

Yep, sounds like a solid plan.

@Baer
I always do this maintenance before any issues pop up. A lot of people wait until something’s wrong, and by then, it’s too late. Doing it as preventive maintenance is usually the way to go.

CarEnthusiast said:
@Baer
I always do this maintenance before any issues pop up. A lot of people wait until something’s wrong, and by then, it’s too late. Doing it as preventive maintenance is usually the way to go.

Makes sense. Should I do it now or wait until 60k? I keep hearing mixed recommendations.

@Baer
If it were my car, I’d flush it now to get rid of the old fluid. Then stick to regular drain and fills.

@Baer
I did mine at 60k, and the car felt more responsive afterward. You’re probably okay waiting until 60k unless you’re driving in tough conditions.

Milo said:
@Baer
I did mine at 60k, and the car felt more responsive afterward. You’re probably okay waiting until 60k unless you’re driving in tough conditions.

Oh, and it was $399 plus tax for a drain and fill at the dealership.

CarEnthusiast said:
Won’t hurt! Go for it! But I’d suggest only going to the dealer or someone who really knows Subarus.

Are you serious?

I’d just take it to a Subaru dealer and ask for a CVT service. Probably a drain and fill, but that’s safer than trusting a random shop.

Drain, no flush.