Transfer Case Issue?

Morning,

Just looking for some suggestions. I own a 2012 CX-9 GT with 53,000km (33,000 miles). About a month ago I noticed a loud humming sound when driving on the highway with the steering wheel in a straight position. When the steering wheel was turned slightly to the left or right, the humming would stop. If I applied the brakes or pressed the accelerator, the humming would stop. If I maintained a straight course, the humming would return. I took the car to my local mechanic and he checked the front wheel bearings, which were fine. He rotated the tires and told me to keep an eye on it.

Two weeks ago I was on the highway again and got the same humming sound, which got really loud. Almost sounded like something was rubbing. I pulled to the shoulder and pressed the brakes and the sound stopped. I tried moving forward again, accelerating to highway speed and the sound didn't return.

Few days ago I was on the highway again. Heard a mild humming sound when the steering wheel was straight. Turned the wheel to the right and the sound stopped. Turned the wheel to the left and the sound increased, with a vibration that even shook the gear shifter. As I straightened the wheel the vibration would stop and the humming noise would decrease. When I pressed the brakes the sound would stop.

Mechanic believes it could be the transfer case. My CX-9 is still within the 5 year powertrain period but before I go to the dealership I'd like to hear some opinions/ideas.

The humming sound isn't constant on the highway when the steering wheel is straight, it's intermittent. It also doesn't start until I've been driving on the highway for about 45 minutes. During city driving, there's no humming whatsoever. Also, the humming sound progressed to a vibration as well but only when the steering wheel was turned to the left.

Any ideas? Possibly the transfer case?

Thanks in advance.

Honestly, it doesn't sound like a transfer case problem, you can quickly check this by getting under the car and check for any dark grey leaking oil or an super intense acrid pungent smell. Have you ever changed the transfer case oil ? @ 33,000 miles, should have done it a long time ago, like 15,000 miles: http://www.mazdas247.com/forum/showthread.php?123847373-Changing-CX-9-transfer-case-gear-oil-%28photos%29

It sounds more like a steering issue, because you only hear the sound depending on the steering wheel orientation,
if it was the transfer case, you would be hearing it no matter what steering wheel orientation.

just FYI, there was a recent recall issued for 2013-2015 steering knuckles :
http://repairpal.com/recall/16V203000

also, did you get the lower control arm recall done ?

I'm taking it to the dealer tomorrow morning so I'll ask them to change the transfer case oil. It's never been changed and I've never noticed any leaking oil or strong smell under the engine.

Looks like my CX-9 was manufactured prior to the dates shown on the recall for the steering knuckle, and yes, I had my lower control arms changed under the recall a few months ago.

Thanks for the info, it's much appreciated.

CX9-er said:

I'm taking it to the dealer tomorrow morning so I'll ask them to change the transfer case oil. It's never been changed and I've never noticed any leaking oil or strong smell under the engine.

Looks like my CX-9 was manufactured prior to the dates shown on the recall for the steering knuckle, and yes, I had my lower control arms changed under the recall a few months ago.

Thanks for the info, it's much appreciated.

Click to expand...

no problem, glad to share any info that might be helpful to a fellow CX-9'er,
be prepared to have dealer say "Transfer Case is a sealed unit, it cannot be serviced"
a lot of AWD owners get that same excuse from dealers because there is no drain plug and the old oil sludge needs to be pumped out, most dealers don't offer that service thus a lot of the members here do it themselves or take it to the their local shops to get it done. But believe me, it needs to get done. My original transfer case broke and it was fixed under warranty thank god. I had no idea about the high rate of transfer case failures until mine broke and I searched and found this forum. There's even a youtube video now, many thanks to fellow member "kulkarnipb"

CX9-er said:

I'm taking it to the dealer tomorrow morning so I'll ask them to change the transfer case oil. It's never been changed and I've never noticed any leaking oil or strong smell under the engine.

Looks like my CX-9 was manufactured prior to the dates shown on the recall for the steering knuckle, and yes, I had my lower control arms changed under the recall a few months ago.

Thanks for the info, it's much appreciated.

Click to expand...

What was the cause for the sound ?

Sorry for the late response. After a couple of visits to the dealership, it was determined that there was a problem with the drive shaft and it was replaced under warranty.

CX9-er said:

Sorry for the late response. After a couple of visits to the dealership, it was determined that there was a problem with the drive shaft and it was replaced under warranty.

Click to expand...

Glad to hear you resolved your issue. I had my car in for a bad brake booster last week, covered under a warranty extension program. While waiting at the counter, I saw some of the service advisor notes on my car, and there is another campaign that was included, but not marked "closed out" like the lower control arms was marked (work performed in February)--transfer case. Some models have warranties extended to 84 months / 90,000 miles:

http://am.mazdaserviceinfo.com/libr...ls/en_us/pdf/SSP92_Dealer_Letter_Attach_I.pdf