Humming Noise - 2013 CX-9 AWD

[a.zakariah]

Hello everyone, I'm reaching out for help because I'm exhausted from spending money and time on my 2013 CX-9 AWD. I purchased the vehicle two years ago, and after a few months, I started experiencing shuddering, especially while driving uphill. I found a temporary solution by using Lubeguard's quick shudder fix, which worked for about a year. Unfortunately, the problem returned, this time accompanied by a humming noise that starts as soon as I drive and doesn't go away.

I've taken the car to multiple mechanics, and each one has suggested different issues. One mechanic indicated that the AWD is the problem and suggested disabling it to resolve the issue. Another said the problem lies with the AWD and the torque converter, recommending that the torque converter be replaced and the AWD system disabled. Another mechanic even mentioned that the entire gearbox might need changing.

I'm feeling quite confused and unable to decide what to do, so I took the car to another shop. They initially thought the humming noise was due to a wheel bearing, but after inspection, they ruled that out. Then they suspected that the differential oil needed changing, which we did, but the problem persists.

I would genuinely appreciate any advice on what might be causing these issues and what steps I should take next. Thank you! By the way, I had the transmission oil changed just a few weeks ago.

 

[rowlands57]

Have any of these shops looked at the PTU that is in the front of the vehicle that drives the rear driveshaft. It's a well known issue on these models with the Ford drivetrain. They decided that the PTU is not servicable and has lifetime fluid.

What happens, over time, is the factory fill turns to sludge. If you can find a shop that will vacuum out the sludge and replace it with a good synthetic gear oil that may help.

 

[Bronco Boy]

They are all correct, but now somebody needs to go deeper and find the exact cause.

The fact that lubeguard bandaided the problem would lead me to focus on the transmission.

 

[sarpworks]

if it helps; I felt vibration and humming noise before awd failed on my 2011. it was coming from bearing/s on drive shaft.