One of the first ‘big’ maintenance items I decided to tackle as part of my 88k maintenance adventure was the CVT transmission fluid flush. I did tons of research and watched a handful of youtube videos. Its a pretty straightforward process. I wrote up the procedure, as I understood it from all of my research, then had ChatGPT verify it and format it for me and put it into a guide I could follow.

CVT fluid change instructions that I followed

Tools and Supplies

Item Notes
Subaru CVTF-II 7 qt
CVT drain plug washer Part # 803916010
Filler plug gasket Part # 803918060
Fluid transfer pump
Graduated drain pan
14mm socket For drain plug
8mm hex bit socket For filler plug
Torque wrench
Ratchet and extensions
Jack, jack stands, or ramps
Wheel chocks
OBD scanner (CVT temp capable) Needs to read CVT fluid temp
Gloves, rags, eye protection

Specs
CVT fluid Subaru CVTF-II
Total capacity 12.0 US qt
Drain-and-fill amount ~7 qt
Final level temp window 35–45°C (95–113°F)

Torque Values

Component Torque
CVT drain plug 31 N·m / 22.9 ft-lb
CVT filler plug 50 N·m / 36.9 ft-lb

Supplies

I had to delay for a weekend because I needed to order a couple tools and the supplies I needed. Based on my research using OEM Subaru CVT-II fluid is recommended. Apparently the Subaru CVT is sensitive to the fluid and using non-OEM can have mixed results. I will say, Idemitsu, the OEM manufacturer of Subaru’s CVT fluid, has their CVTF SB2 fluid for sale that is allegedly the same exact fluid (or better)for ~$13/quart vs the $16 I paid at my local Subaru dealership for the OEM fluid.

I decided to spend a couple extra bucks and go with the OEM fluid. If I had to do this maintenance more often I might be more price sensitive but since I may only have to do this 1 possibly two more for this car, I figured OEM is worth the ‘premium’.

I also bought a torque wrench, a pump/hose to pump the fluid into the fill hole, and some hex bits since my tool kit didn’t have the sizes I needed.

Supplies fresh out of the box

Everything laid out and ready

Getting the Car Up

Like any DIY project, I spent way too much time just getting ready to even start. I had to clean off my ramps that I’d left in the elements near my shed. They were covered in dirt/muck and came complete with an entire ant colony that I had to spray off.

I got to spend the rest of the project with ants wandering around the ground where I was laying. Cool!

Freshly cleaned ramps

Ramps ready to go

I got the car jacked up and leveled out. It doesn’t need to be laser leveled but it should be roughly level so your fluid readings are as accurate as possible.

Car up on the ramps

Checking that the car is level The picture makes it seem less level than it was. Jack stand in place Always use jack stands!

Under the Car — and the Issue

I crawled under the car and immediately noticed a problem with the CVT.

The CVT drain pan looked “wet” and when I looked at the bolt it was clearly leaking. When I say leaking I mean, it was noticeably wet and dripping fluid. Drain bolt already wet — it was leaking

The ONLY way this happened is if the dealership tech either:

  1. accidentally opened it while I was getting my oil changed the 2 weeks prior
  2. did the CVT service instead of the diffs (and did it poorly).

So I was a little annoyed.

I decided, with the amount of fluid it looked like it was leaking, and since I was already planning on doing the service, that I would just finish. Then I’d take it to the dealership to have it documented and make them confirm they did the diffs that I paid for. The cause of the leak: a missing crush washer. And the drain plug was pristine. There is no way in hell this should be pristine unless someone recently wiped it clean…

Drain

CVT area with undertray removed Old fluid drained and measured

Drain plug with the new crush washer installed

Refill

Fill plug removed

Refill in progress

Getting to Temperature

Meanwhile, Back from the dealership…

I got it buttoned up and went to the dealership to make them verify my diffs were done properly. I didn’t have a ton of faith that the service I paid for was completed. I thought maybe they did the CVT (poorly) instead?

They put it on the lift and showed me the diffs were done. They were annoyingly skeptical of my leaking CVT story even with the videos. But all in all they were pretty cool about it.

They didn’t admit to anything and they were skeptical that maybe I screwed something up. I’m sure they’ve heard wild stuff from shady customers so I dont really blame them for being wary. But I showed them the video and they looked at my service history. When they looked it up and realized that I always brought it to them for everything and I was just in 2 weeks ago for service they softened a bit. The service manager is going to have them check the CVT level next time I come in for a service. My transmission was too hot for them to do anything about it today and I didn’t want to wait 4 hours for it to cool down. (Hilariously), they seem worried that I didn’t do the service properly.

They are putting a note in my file to do it next time I come in when I can leave it for longer.

They also tried to go back and look through the videos and photos that they take during their inspections (the grainy ass ones they text you) to see if they could see it dripping. The service manager said the techs would’ve said something if they saw it. They also told me that the tech that did the last work on my car is a pretty seasoned tech, that they don’t have issues with, so they’re pretty sure he wasn’t the one to have done that. My response to that was, the tech that’s on the paperwork might not be the tech that did my diff service. I am sure you dont have a senior tech doing oil changes so whoever was doing the oil changes that day probably screwed up and started to drain the cvt, panicked, put back the bolt (without the washer), and screwed it in. The shop foreman asked me if I’d seen any stains on the ground in my driveway and I said “No, I dont think I have”.

The conversation got to a point where I just said, “Look, I know I didn’t do it. You don’t have any reason to think that your guys did it. I just want it documented in my file that this happened so that if anything comes up down-the-road with this transmission, we can fight about it then.” and they all laughed. Part of this blog is to document it for posterity on my end.

Gotta say they got it up on that lift and did all that stuff so much faster than I did with those ramps and the jacks.

When I got home I looked at my driveway and realized there were actually quite a bit of stains on it from CVT fluid. I guess my brain never registered them as more than “AC condensation drips”.

Those aren’t AC condensation drips

At the rate it was dripping when I crawled underneath and the amount of staining I had, there is no way this DIDNT happen at my previous service. IF it happened 2+ weeks before, my CVT would have run low on fluid and grenaded well beforehand.

So in a twist of fate, this wild hair I got to work on my own car caught this pretty serious issue before anything major happened.