A few weeks ago this weird humming noise started up. It is a constant noise that gets louder at higher speeds and is nonexistent at very slow speeds (i.e., parking lots). When I swerve to the left, the noise goes away. When I swerve to the right, nothing happens. At speeds from 30-45mph it is louder when I am coasting. At speeds above 60mph, it happens when I am coasting down hills and also accelerating.

I took it to the dealership and took the tech for a ride, he said it was most likely a wheel bearing. Took it to a very reputable independent Toyota shop, took the tech for a ride and he agreed about the issue being the wheel bearing.

So, I ended up leaving it with the independent shop to get the wheel bearing replaced. I get a phone call this morning, they replaced the wheel bearing but the noise is still there. They are currently trying to diagnose the issue again, but have had no luck.

Any input?

Thanks in advance.

Update: Shop called and they tested my front and rear diffs and my transfer case fluids. The transfer case and the rear diffs were perfect, but the front diff fluid was black.

I changed all three 16,000 miles ago and put in Mobil 1 75W-90. When they changed the front diff fluid out, the sound got worse. Now we wait...

Anyone have any clue as to what is going on here?

Can you hum a few bars and help us out?

baddaboom

I'm having the same problem on a 1Gen Tundra. It's been narrowed down to a differential bearing. Taking it in on Thursday to have it replaced.

No ideas, having the same thing (down to the go away at off center as well as moh) and though my mud tired need to be rotated. Now maybe more.. Will get them rotated ASAP and get back with ya.

I have a v8 4x4 05 too.

Front diff was on its way to biting the dust. Luckily, I found a wrecked T4R at the local yard with 60,000 miles and the diff was in great shape. Getting the new diff put on in the morning.

Check to see if 1 or more of brake calipers are seized. Use wheel chocks and jack stands for safety. Engage your E-brake, put it in neutral and jack up the front (both wheels up) and you should be able turn the wheels by hand.

even though it is not resolved, its good that the pros can hear it too and you're not the only one. nothing is as frustrating as when it seems as though you're the only one who can hear some noises on your vehicle!

Update: New front diff didn't fix the noise. Luckily, this shop isn't charging me for any of the work. They're putting my old differential back on and giving me back my truck (I need it back ASAP and already missed 2 days of work unnecessarily).

Caliper pistons aren't seized either.

This is getting pretty frustrating....

If you find out what this sound is, please share... You are describing exactly the same situation that I am in right now.

Well, the shop put my old diff back on and I took the truck over to the dealership to see if they can figure it out...

Hopefully they will figure it out in the morning, I'll keep you posted.

rotated my tires to no avail. Toyota dealer says it is a bad wheel bearing. $500 repair. fingers crossed it does the trick.

i just had the same problem a few weeks ago. made a humming noise and got louder when i accelerated and when i shifted into reverse or drive there was a klunk or a knock. went to autozone and got a new universal joint for 15.00, pulled the drive shaft out and replaced the front joint and it fixed it.

sounds like the same problem but could be totally different

i replaced my CV axles at the beginning of the summer. drove around for a few weeks and then out of nowhere a similar sound (if not the same) popped up. ITS GAWD AWEFUL. Went to drain the diff fluid and it was almost empty. I put new fluid in hoping it would be a simple fix... but nothing. i have a 97 4Runner. I am scared to find out what it really is. but i cant drive it on the highway. it scares the bejezus out of me.

Recently took my 04 into the shop to have the right front wheel bearing replaced...because that is where the noise was coming from, the right side. Turn to the right, it would go away...turn to the left, the noise was still there.

The mechanic replaced the right bearing, noise still there. After a bit of confusion, the mechanic pulled out the left wheel bearing...it was toast.
I take the blame, I told him to replace the right bearing because that what I believed was bad. Evidently it isn't always easy to pinpoint what side the issue or noise originates from.

Andy

what did you pay for a bearing to be replaced?