Hello Everyone!

I bought a 03 4Runner with 99k about two years ago. For the past two months, I am hearing a fairly loud humming noise coming from the front that changes with speed; the faster I go the louder it gets. I thought initially it was the front wheel bearings so I replaced both of the front hub assemblies. That did not fix it. Also, when I changed the inner seal, one of the seals was in pretty bad shape.

When I am on the highway, when the suspension lifts up because of bumps/humps on the road surface, the noise subsides a little. As soon as the suspension settles back down, the noise comes back as loud as it was.

When I turn the wheel, at highway speeds, the noise does not change. When the road surface changes (ie. from concrete to asphalt) the noise does not change.

I am thinking it might be the CV axles but I am not sure. Everything I read on this forum and others seems to indicate I would be hearing a different sound (clicking) if my CV axles were bad.

Anyone have any thoughts on this?

Thanks!

John

V6 or V8?
V6 has the front diff needle bearing issue on the driver's side.
Could it be a tire issue, does rotating tires affect the noise?
Possibly a brake disc shield rubbing on the disk. CV metal seal/shield rubbing on diff or steering knuckle.
Just throwing ideas out there.

Edit:
Seized front caliper

It's a V8. I didn't consider the tires making the noise. They are about a 1.5 year old and haven't been rotated yet. It does sound like tire noise but I would think with going over the different road surfaces the sound would change. Plus one other thing, when I am at a light, and I let my 4Runner creep up, it feels a little "clunky" when it moves up bit.

I am just hoping it is not my front diff going bad or something. I think with the suspension travel and the noise being affected by it, I am guess the front diff is not the issue.

Did you diagnose this issue..?
I have the same type of noise in a 2016 SR5 @ 25-45 MPH (88K mikes) goes away when I'm in 4wd.. replaced the wheel bearing thinking that's what it.. NOPE!

I just sent you a PM. I have a V6 that has this same vibe that has steadily gotten worse over the last 5K miles. I've replaced CV, U-joint, Hub/bearing, full tranny service/fluid exchange, shudder additive (didn't need it, but tried it too), special Toyota wheel balancing using the lug centric tool, checked calipers. Came across a post that referenced the needle bearing in the driver's side. Known problem affecting 05 and up including brand new 5th gens that have had the needle bearing and/or entire front diff replaced (sometimes multiple times) under warranty. Also a problem on FJC and Tacos. Same diff on the V6. I'm ordering a brass bushing to fix the problem and hoping the needles didn't do too much damage to the front diff. You can check it by putting it in 4wd and seeing if it changes the vibe at all (looks like yours goes away). It did for mine, but didn't totally eliminate it, so I suspect diff damage. Heres the link: TOYOTA 8" CLAMSHELL CV AXLE BUSHING

The V8s with similar symptoms usually have a bad U-joint(s) on the front drive shaft.

Watched every video I could find and removed the needle bearings.. put in the ECGS bushing in.. took about 4 hours.. no more noise

TOYOTA CLAMSHELL BUSHINGS - 2003 & Newer 4runner and GX470

Glad it worked for you. Mine didn't. I'm starting to wonder if the new hub I put in has a bad bearing or if it's a motor mount or possibly left rear bearing. Vibe/hum is there from 65 -75, but goes away if I turn the wheel slightly to the left and also changes with suspension movement - dips/bumps in the road. Any other suggestions are welcome. I don't understand how the rack could produce a vibe at speed, but not at any other speed.

did you ever fix it? mine fits this description to the t. loudest at 70mph, quite a bit quieter at 80. noise goes away completely if i bank to the left. sounds as if it's coming from the front left.

I'm experiencing the same issue. At first it was only at 50-60 mph. Now it's started to happen semi frequently even at lower speeds but still worst at higher speeds. Slight turn makes it stop.

My uncle was suggesting it could be the CV joint which based on some research I cannot rule out.

For now I've purchased some new front bearings in the hope that they are the culprit. I'm a little nervous it's not them though because I didn't notice the play in the wheel that others had mentioned.

what is the noise you're hearing? cv axles clink and clunk when they start going out. You should typically be able to reproduce this consistently by turning to one side or another under low speed with throttle input. I guess it's possible for cv's to hum as well if they've been leaking and low on grease/watered down grease, but it typically is accompanied by clicking. If you have humming, it's wheel bearings 99 times out of 100. Even without excessive wheel play. Wheel bearings are easy enough to replace, and with the miles you have on it wouldn't hurt to get them replaced anyhow even if they aren't the issue yet.