u/RedditOldGuy500

I’ve posted a few CVT fluid change questions here before and have always appreciated the responses and discussions.

I recently called my dealer to ask how much a CVT fluid change would cost at 30K miles on my daughter’s 2024 Mirage G4. They quoted me $330. When I asked what that included, they said it was a complete flush using their machine (I’m hoping it’s not like the old flush machines from years ago… I assume it isn’t). So I imagine that means all—or nearly all—of the fluid would be replaced. That was the full extent of the service, with no external filter change included.

If I were to do it myself, I’d likely go with a drain-and-fill, which would replace a little less than half of the fluid, along with changing the external filter. I would also document everything—similar to how I record my oil changes for warranty purposes—using photos and video, so I have a record in case of any future CVT warranty claims.

That got me thinking: would I actually be covered? The dealer would be replacing all (or nearly all) of the fluid, whereas I’d only be replacing about half. Would that difference matter from a warranty standpoint or either way it was "serviced" and that is what matters?

Appreciate the thoughts!

I’m posting this in a few different forums to get some clarity on my questions, and I’d appreciate any insight.

I’m working on my daughter’s 2024 Mitsubishi Mirage G4 and am approaching the 30K transmission service. I plan to do a drain-and-fill along with replacing the external plastic filter. I initially thought everything was straightforward, but then I started reading about the CVT fluid deterioration counter.

I have a bi-directional scan tool, but it does not reset this counter. From what I understand, resetting it may be necessary so the CVT can properly adjust to the new fluid. While researching here and on other forums, I came across the ELM327 v1.5 OBD2 adapter and the CVTz50 app. It seems there are relatively inexpensive (~$25) dongles available that can perform the reset. However, I’ve also read that using them can sometimes trigger warning lights on the dash, requiring the car to be cycled on and off a few times to clear them.

So, I have a few questions:

1. At 30K miles, is resetting the deterioration counter even necessary? Since a drain-and-fill doesn’t replace all the fluid, the new fluid mixes with the old, so a full reset doesn’t seem entirely accurate. So, maybe at 60K when dropping the pan reset it then.
2. If an issue arises, will the dealer check the deterioration counter? Even if I thoroughly document the service (I record my maintenance for documentation), could a warranty claim be denied because the counter wasn’t reset?
3. I’ve done my own automotive work for many years and am very familiar with bi-directional scan tools. Still, it feels odd to interact with a module in a way that may temporarily generate errors requiring multiple restarts to clear. Is there any real risk of damaging the module? I don’t mind buying the dongle if it’s safe to use.

My goal here is simply to maintain the CVT properly and keep everything in good working order while preserving the warranty (hopefully never needed). I hope this all makes sense, and I appreciate any guidance.

Thank you everyone!