(As a preface, I also posted this on the Engine/Turbo/Drivetrain page just in case people are only browsing one section of the forum)

What's up everybody! After many years of waiting, I finally joined the Evo club a couple weeks ago when I bought my 2013 X GSR. Every single time I drive it I fall more and more in love with it. I apologize for the wall of text but I want to be as thorough as possible explaining what's going on.

Yesterday afternoon I began to experience a really strange deepish groan noise. The first time it happened I wasn't sure what to think of it, and I unfortunately can't recall how I was driving when it happened. I was on my way home and it happened one or two more times when accelerating in 3rd gear under non-strenuous driving.

After leaving it parked for a few hours, I went to go get gas for the week and made an effort to try and record it happening, so I recorded every single time I went from 2nd to 3rd and continued accelerating. I managed to record it happening 3 times I believe, with only 2 turning out good; although 2 friends I sent the video to had a hard time hearing it since the window was rolled down. If you can hear it clearly enough, the noise happens right after my blinker clicks off and I accelerate relatively normally in Tarmac mode. The second video is of me casually accelerating onto the highway in 3rd gear while in Tarmac again. I did not get a video of it, put pulling away from the gas pump in 1st gear very slow and casually it made the noise again. That's the only time it ever happened outside of 3rd gear.

https://www.youtube.com/watch?v=GtKD...ature=youtu.be

https://www.youtube.com/watch?v=W6a2...ature=youtu.be

After I got back home obviously paranoid, I began searching for anything I could find regarding the noise. I saw one guy say that he had a somewhat similar noise occurring at certain intervals and it ended up being the AYC pump filter being sucked up. I also read another post saying that to test if it's the AYC pump, you can put it in Snow mode and see if it gets worse, so I took the girlfriend with me and had her record the next 3 videos.

Video 1 is accelerating in 3rd gear while in Snow mode.

https://www.youtube.com/watch?v=dSTW...ature=youtu.be

Video 2 is some accelerating and braking in Snow mode.

https://www.youtube.com/watch?v=TNPt...ature=youtu.be

Video 3 is the noise happening while heavily braking in Snow mode.

https://www.youtube.com/watch?v=bVOO...ature=youtu.be


The odd thing to me is this noise is somewhat rare, happening at random times, only during acceleration while in Tarmac mode and Snow mode, but only while braking in Snow mode. Today I drove to work carefully in Snow mode to see if was still occurring, and it happened once in 3rd gear while accelerating and once in 4th (only time it's ever happened in 4th) and once while braking.

From what I can tell/what I've had friends tell me they think it's either the AYC pump or something with the rear diff. The girlfriend said the noise definitely seemed to be coming from the rear of the car. The guy I bought the car from, who I have been in somewhat regular contact with since purchasing it, had the AYC pump replaced under warranty at a Mitsu dealer just this past winter. The car is still under factory warranty for the rest of the year so in theory I should be fine, but I wanted to post and see if anyone had ideas before I give the dealer a call and get an appointment.

Sorry again for the wall of text, and if I need to clarify or add anything, please let me know! Thanks!!

 

I know this post is a little older, but I came across it when I was looking for a solution to my issue, which happened to be the exact same.

I got it fixed the other day and all I had to do was bled the air out of the system. No issues or noises since.