rodeopunk_je87

iTrader: (1)

So, here in Illinois the temps dropped dramatically on Monday. And when I got back to my car after work (it basically sat outside for 12 hours in 0 degree weather), I started the car and let it warm up for like 10 minutes (til I saw at least one bar in the temp gauge). When I went to pull out, I started hearing a high-pitched whining noise coming from somewhere near the rear of the car. It went away after about 10-20 seconds of driving.

***just to clarify...the noise only occurs when the car is moving, not stationary. Noise is there regardless of gear or RPM, it even does it in neutral. However, it goes away after moving for a little bit. The loudness and length of the sound is negatively correlated with the temperature outside and length the car has been sitting there


The next morning (after sitting outside for 14 hours in colder weather), I fully let the car warm up and started to record on my phone as I started to drive, and there it was again...


I got up to about 10 mph and put the car in neutral, and it still did the noise. So, I know that it's vehicle speed related and not RPM related. It also seems (not 100% sure) like it has something to do with the transfer case and not an ACD pump since it does it in neutral, too.

Any idea what it could be? The temps are still super cold up here, so I have tested to see if I heard the noise in warmer weather, but I'm worried something may be wrong with the car.

Any help would be appreciated.

Vehicle Details:
2011
GSR
~10k miles

zebra4

The EXACT same thing happens to my 2011 RA when cold, and only for about 10-20 seconds. I have yet to figure it out, but it does it every single day twice a day when its below -10 celcius. It has been doing it since i bought it 2 years ago, only in the cold. I have not seen any negative side affects so far, so i wouldnt be too worried it i was you. BUT i am still curious as to what causes this...

Also, once you have started moving the car, try stopping. With mine, the sound goes away if i stop, but comes back when i start to drive again. This leads me to believe that it is a moving chassis component causing the sound. But again.... i am not sure.

rodeopunk_je87

iTrader: (1)

Hey man, thanks for your input! I've had several discussion with our local Evo X group, and several people have had the same issue this passed week. While, we've had many days when temperatures are below freezing, it appears to only happen when temperatures go below 10 degrees Fahrenheit.

Let's hope someone on here has a good answer.

In the meantime, I ask (if you haven't already) that you please contact Mitsubishi about the issue. I just want to make sure they have it full documented, and if it is a part that is failing, that they have enough volume of calls that they maybe issue a recall. This way, owners who's warranties have expired, can have the issue repaired.

Thanks,

AWDTerror

iTrader: (2)

I would say the diff pumps in back. They still operate regardless if the car is moving or not.

Sunwalker12

Couldn't tell you what it is man, though my Wife's '12 Expedition does the same thing during cold weather. Goes away once the motor is at operating temp though. I've tried figuring it out and no luck to date...

rodeopunk_je87

iTrader: (1)

But the car only makes the sound if the car is moving. So if they still worked, even when the car is not moving, I think I would hear the sound when I'm parked.

Sunwalker, I never move the car unless it's gotten up to a decent temperature. May not be full operating temp, but definitely warmed up. And the noise only starts when the car begins to move....so far, we've identified two possible sources: the transfer case or the differential.

Buru_EvoX

I think your car is haunted. Might want to call Ghostbusters.

Sunwalker12

Very well....I venture out to say that its probably your diff if its only when your moving. Could be the carrier going bad, open the fill plug and stick a magnetic retrieval tool in the diff....see if you can recover any shavings. Another possibility is that the fluid needs to be replaced with a different viscosity to prevent any nosie during operation in colder temps. The transfer cases on the Xs are fairly strong and it would take a lot of abuse to ruin them prior to the rear diff (the weak point on the drivetrain)...

rodeopunk_je87

iTrader: (1)

Thanks for the input!

szuto

I am also getting that noise also! The weather has been fairly cold outside (-20 to -15). It's fine in the morning because I park the car in the garage.

I only get this noise if the car is in motion and, goes away once the car is fully warm up.

TheNEWB

same noise here in my 2009 Ralliart, only when temp is -10. In about 1km of driving the noise goes away.

Gqracer

iTrader: (1)

It's the AYC pump. If u back up, the sound will go away and come back on. My does the same thing also during a long drive. The sound is louder in the garage or near a wall because the sound bounces back. Good luck

rodeopunk_je87

iTrader: (1)

But the sound is produced even when the car is moving in neutral. I though the AYC pump only works when there is torque traveling down the drivetrain?

rodeopunk_je87

iTrader: (1)

If it was the diff going bad, wouldn't the sound be reproduced under extreme driving conditions? It appears that the volume and length of the sound is strongly correlated with how low the temperature is...

Then again, I'm no mechanic...

AWDTerror

iTrader: (2)

AYC pump is always cycling, you can look at the reservoir in the back and watch the fluid level go up and down.