I have a 2009 g37x automatic coupe with ~22,000 miles on it and everything has been great until recently. Within the last 3 days or so I have noticed that when I pull into a parking space or turn sharply at low speeds, the car vibrates pretty heavily. The sound and feel is extremely similar to a manual car stalling out. I have tried turning the A/C on and off and tried snow mode and nothing seems to change it. The RPM's are not dropping out like a stalling car would. This occurs no matter which direction I turn and the harder I turn, the more severe the vibration. In normal driving, it is not noticable but when parking, the entire car shakes. It seems to be getting worse and I wasn't sure if this was a common problem with the car or not. I have looked all over this board as well as others and some people seem to think it might be the power steering reservoir. It almost feels to me as though the differential is locking up or something. Let me know if I can provide any more information for you all to help my diagnose this problem. Thanks

-Matt

 

Usually it is the power steering. Check the fluids and see if you have enough in there. Is your alignment weird as well? If so, check your bushings on your axle. That was a problem for my old Lexus.

 

as chris said, might be power steering fluid low (but i honestly don't know where it could be going)

might be the serpantine belt loose which in turn isn't turning the PS pump or making it slip. might wanna check that too.

 

*Update*

So last weekend I went and drained both the front and rear differential fluids. I refilled them with 75-90 synthetic in the rear and 80-90 synthetic in the front. I also added a friction modifier to both to hopefully cure this problem. Though the problem does seem a little better, the car is still having issues. Based off the symptoms, I am still feeling that it is an issue with the differentials.

Driving straight, you would never know the car had a problem which makes me want to rule out a problem with the CV axle or wheel bearings. When turning at about 40% of full turning capability or further (left or right, forward or reverse) the car begins to vibrate and jerk. It isn't extremely severe but it is absolutely noticeable and concerning. I have not dug into it being a power steering issue yet because when I am not moving and I turn the wheel back and forth, there are no issues.

Now I am curious about learning about the power train on this car. I know I have a front, center, and rear differential on the car. Are the front and rear differentials VLSD? Open Differentials? ect.

Any buddy have any suggestions on what to check next? If you need more symptoms or information, please let me know. Thanks

-Matt

 

It sounds like to electronic coupling in the transfer case is bad. It has been an issue for some awd models.

 

Thanks IMTASE for the info. I looked online and found this issue. I will certainly keep that in mind as a probable issue.

The other thing I have learned with this issue that seems very strange to me is if I just turn the key to "ON", I am able to turn the wheels without the power steering assisting me. When I do this, (Just turning the wheel about 180 degrees and back) the vibration and grinding goes away for several turns. This makes me think it could be an issue with the power steering. I am very confused at this point, haha.