2017 Envision growling noise when in motion

[armworth]

I have a 2017 Envision AWD with about 40k miles. It's been making a growling noise when in motion similar to a bad wheel bearing or snow tires on dry pavement. It seems to be coming from the front. The noise starts at about 5MPH & gets louder the faster you go. Lightly applying the brakes does not change the sound, nor does turning the steering wheel. I jacked up all 4 corners (one at a time) & tried rocking the wheels side to side & top to bottom and there doesn't appear to be any play in the wheel bearings. I spun each wheel as fast as I could by hand but it did not reproduce the noise. Another thing I tried was shifting into neutral at about 40MPH but that had no effect on the noise either. I checked the center carrier bearing for the rear driveshaft...it seems to be OK but when I was underneath I noticed the rear differential is very oily, so I guess I'll be taking to the dealer to have it checked out.

I'm wondering if the noise from the front could be a bad bearing in the transaxle or maybe just low fluid? Unfortunately there's no dipstick so I might try pulling the driver's side front wheel & removing the side plug from the trans to check the fluid level. If none trickles out, I'll just top it off until it starts to drip.

Anyone encounter a noise like this before or have any suggestions? Thanks.

 

[armworth]

I pulled the side plug from the transmission & about 8 oz of fluid trickled out. It was black & smelled burnt. I took the Envision & a sample of the fluid to the dealer yesterday. One of the mechanics & I took it for a ride & he said he's never heard such a noise before. He tried all the things I tried - light braking, turning the wheel back/forth, shifting to neutral, turning the engine off & coasting, etc. He said it seems to shift OK so hopefully the trans just needs a flush, but the noise is obviously a concern. I left the vehicle overnight for a diagnosis. They called about noon today & said the problem is with the rear differential. They said it will take about a week to get a replacement & advised against driving it. The differential repair will be covered under the drive train warranty but he wasn't sure about the trans. If just a flush & fill, there will be a charge, but if other work needs to be done, he might be able to have it covered under the drive train warranty.

I'll give an update when I can. Hopefully it will be helpful to anyone else with a similar problem.

 

[armworth]

The parts finally came in & we got the vehicle back. Parts & labor for the differential repair were covered under warranty but the charge for the trans flush & fill was almost $300. We were told that there was a noticeable vibration during the initial test drive after the repair. The driveshaft was replaced & that cured the vibration. They suspect the original driveshaft went out of balance at some point (lost a balance weight?) causing the bearing in the differential to fail.