Whirring noise - rear diff/tire - question?

Hi, 3rd Gen DCLB 4x4 sport owner here with about 42k miles (2019). I get all factory maintenance done at the dealer and haven't skipped any. I had a whirring noise that was coming from my rear wheel, mostly the passenger side. It's more pronounced at faster speeds.

The dealer said it was likely the rear differential. The mechanic found metal shavings when they drained it and said it needed to be replaced. Fortunately, this was covered under warranty and they replaced the rear diff for free (it's like a $2k part!).

Unfortunately, the noise is still there. I took it back to the dealer and they had the shop foreman look at it. Supposedly they checked all the suspension parts and the rotor ect. They concluded it was tire chipping and I should replace the tires, maybe the tire went bad with a slipped casing.

The tire are 1.5 years old, Cooper discoverer AT3. I've put about 20k miles on them. The tread depth has plenty of life and there are no signs of uneven wear (they are 60k mile tires). Toyota does not do warranty claims for tires so I took the truck to a tire shop that processes claims (Pep Boys).

The tire shop looked at the tire (took it off the rim) and said it was just fine. They didn't see any issues with the tires but did confirm that they hear the noise as well during a test drive. The tire shop mechanic gave me a free rotation to see if the whirring noise moved to the front (if it was a bad tire).

So...the tire shop says the tires are just fine and it's likely a mechanical issue on the truck. The Toyota dealer says they don't see any mechanical issue and I should just replace the tires. But the rotation of the tires didn't move the noise.

Anyone have an idea of what this could be? Due to the rotation I'm inclined to think it's not a tire issue but something mechanical. But the dealer said they checked everything out. I guess I could go back to the dealer and have them put on new tires and see if the issue is still there. I'm confused and at a loss of what to do.

Any thoughts, tips, or idea would be greatly appreciated!

 

Mount a GoPro down there and see if you can figure out where the sound is coming from better. Can you feel it in the truck when it happens...like vibes? Could be wind noise as you speed up. Good luck.

 

Might be the common/typical diff howl. Is present in many 2nd and 3rd gens.

 

Well it's not the tires because you rotated them. Back to the dealer and ask them to find the problem. I hate dealerships.

 

Put the spare (different tread pattern hopefully) on the right rear and see if that helps. Could always take it to a dyno shop and see if they will hook you up for a quick sesh. Be cheaper than a set of tires...

 

Wonder how this turned out.

I’m having a similar issue but oddly I only heard it the other day after installing a rear diff skid plate.
It’s a low cyclic noise that is pretty noticeable inside around 20 mph and up.
Tapping the brakes doesn’t make it stop unless I slow below 20 mph.

I mounted my GoPro on the axle by the brake hose mount and it sounds very different and is hard to pick it out but inside it sounds like the driveline.

Oddly when I took the skid off it is very difficult to hear, almost impossible. It’s like the diff skid is reflecting the sound up.


Like the OP the truck is dealer serviced and months ago I had all the fluids changed: transmission, xfer case, both diffs.

I’ll have to check the fluid level, but it’s basically quiet without the diff skid.....strange.