High-Pitched Squealing Noise - '16 Limited

Hey folks! I've had a 2016 4Runner Limited for about 1 year, and soon after purchasing it I started noticing this very high-pitched noise. It only happens when it's hot outside (a/c on or off) andI've been driving a few hours (running errands, commuting from work, etc.). It is NOT the brakes (had those replaced to make sure), in fact it stops when applying the brakes firmly. I've had it at the dealership a handful of times and they don't know what it is. I mentioned the bearings, but was told it "too risky and expensive" of a guess to repair.

This is not my video, but it sounds IDENTICAL to this guy's issue. https://www.youtube.com/watch?v=anc4eJsAL6k&t=25s

Has anyone had this issue? Or better yet, has anyone solved this issue? THANK YOU!

 

It definitely is the brakes.

 

Brakes and rotors replaced in July ‘19. Same noise leaving the mechanic. What other parts could cause the noise?

 

The tell tale sign is that it goes away applying the brakes. It that’s the only thing that effects it it’s directly related to it. That means something somewhere is slightly dragging on the rotor. The most horrendous noise I’ve ever heard a vehicle make in my professional career was caused by a leaf. In the fall a leaf got caught up in the brakes. The hard dried up stem just barely touched the rotor but it played it like record. It was like nails on the chalkboard that echoed so loud from the barrel of the wheel. It was insane how much noise it made.

I would bet that as it gets hot and things expand there is something just barely dragging against the rotor. It could be the caliper sticking, it could be the rust causing the pad to hang up a bit, etc. What was replaced in the brakes? Did they replace or reuse the anti rattle shims and the slides because new OEM pads don’t come with new ones. If it’s aftermarket stuff it may be a characteristic of the pad compound.

If you got new pads and rotors I would take it all back apart replace the front slide pins, front and rear anti rattle shims, the rear pad slide hardwear, take sand paper to the friction surface of the pads, just a couple strokes going perpendicular to the direction the rotor slides across them and bevel the edge just a hair so you can ensure the paint they put around the edges isn’t flaking up and causing a squeal. And I’d put it back together using the the purple permeated synthetic brake lube. I’d flush the system as well and get clean fresh fluid in there.

 

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All I hear is wind noise??

 

Air Injection Pump?

 

From the comment section in the video:
"Ok, The noise is solved. the dealership tried to tell me that it was my "Aftermarket brakes" (EBC Brakes), so I replaced them with the factory pads and factory shims. the noise returned in about 12 miles after the replacement. Brought it back to the dealership and the said it was the Right rear axle bearing, as the tech was installing the axle, he noticed that it looked like confetti inside the axle housing and he drained the oil and said it came out as "liquid metal" so the replaced the third member ($2800+ gaskets & fluids). so far, the noise has not returned... it's been two days."

There was no follow-up after this comment so it sounds it solved their issue?

 

Damn, that’s probably not good, so was it low on fluid, or what?

 

That makes sense, wheel bearing failed causing play and movement which allowed something in the brakes to drag.

 

Not sure, that's the only reply to having solved the issue.

 

Hey guys, following up on my initial post. I took my 4Runner to the Toyota dealership this week for uneven wear on the my brake pads. Turns out, the aftermarket rotors were warped and needed replaced...again. Second time in 10 months! I asked if this was something that could be causing or caused by the noise, but they didn't seem to think so. While it was at Toyota, they lubed up all the parts, checked the caliper slide pins, etc. It's going to be a hot day/weekend where I live, so I'm hoping I can duplicate the noise and get it to Toyota so they can hear it first hand.

 

I brought this to the mechanics attention on a previous trip to Toyota, and he said it's WAY too costly of a guess. Said if they took time to open up the bearings, etc. and that wasn't the issue I'd be out a lot of money (my 4Runner is still under warranty - and axle bearings are covered).

 

Any more updates are greatly appreciated.. My 18’ Limited started having the same noise after some mild off-roading last week. I have had this noise coming up on me about a year ago during colder northern climate.. but it went away for a good while till last week.. only happens after spending around an hour on the road.. i could hear it get louder by rolling down the windows.. lower speeds only also(less than 75/80 mph).. taking it to my mechanics on Monday to start on brakes.. if it doesn’t help then i’ll move onto the bearings.. making me want to get rid of this vehicle at the moment.. frustrating..

 

It's definitely frustrating, especially considering what you pay for a 4Runner. No updates yet. It was hot here on Friday and my 4Runner started making the noise, however it poured down rain on my way to the dealership, which cooled down whatever's causing the noise and the noise stopped for the day. Hoping I can get my car to make the noise this week.

 

Any update?
I'm getting the same high pitch screech as the video. It just showed up the last 3 days when the weather has been above 80 deg. Seems to start after about 20 minutes into my drive when I'm going above 25. Doesn't happen during my morning commute though which makes me think heat is a factor. Planning on getting the differential fluids changed this weekend

 

I found a whiny mountain road that descends about 2,000ft and held my brakes the entire way down... the noise went away after that for this entire week when the temperature reached almost 90 on a day or two in TN... I can see with my eyes that one or two rotors of mine have obvious groves in them.. that's why I tried "burning" away if there's anything stuck in there.. Getting a complete brake job done this weekend with powerstop rotors and pads.. let's see if the noise is gone for good...

 

When you had the noise, did it stop while applying the brakes? The high pitch noise I have seems to remain constant regardless of braking (as long as I am going faster than like 25mph). That makes me think mine is not brakes or a warped rotor - but I'm willing to check anything that might fix it. Let me know the results after you get them changed out.

 

will update for sure.. when i had the noise it goes away when i apply moderate to aggressive braking pressures.. dragging the brakes and not slowing down the vehicle much the noise would still be present for me.. check your brakes and see if there's anything visible at a glance.. i'm working my way out from the simplest to the more complicate possibilities..

mine has about 50,000 miles on the odo and has a spacer lift and 33s... everything else is basically stock drivechain-wise.. i also noticed that i have pretty significant vibration on highway speed.. getting my tires checked and rebalanced in a day or two along with the brake job.. the vibration made me afraid it might be a bad bearing somewhere which would be a much more significant fix.. hangin' there.. at the end of the day our 4Runners are still great vehicles for sure.. this is my first vehicle i've ever owned so I am all about finding solutions.. forums are great!

 

No update. I was on my way to the Toyota dealership the other day when it started pouring down rain, causing the noise to stop. So I turned around and went home. It made the noise last night...at 8pm of course, so I couldn't take it to the dealership.

 

Any updates...? I rebuilt one side of my parking brakes recently after yanking the rotor out without loosening the parking brake shoe last time during a brake job messing up my parking brake mechanisms.. after the parking brake rebuild the noise went away for a couple days then it came back... the noise stopped being so consistent.. now the noise kinda just pops for a second or two and then disappears before reappearing right after.. Just called the dealer about it.. might have to take it to them since pulling the rear axle out requires special tools..

running outta ideas now on my own.. hope y'all are having some good luck tackling this problem these days and not have the noise pops on ya... Thanks..

 

Hey! I did a ride-along with the lead toyota service advisor and their mechanic last week. The mechanic said ironically there was a ‘17 4Runner on his rack with the same issue. They spent a few days talking to Toyota engineers and will be replacing the transfer case cap next week. It’s step 1 - if that doesn’t work then they’ll move on to the next. He ruled out brakes/braking components though.

 

Sweet! That's some great news right there to finally have the dealer look at it ha! Best luck to you and them to figure this thing completely out!

I am taking it over to the dealer on Monday.. I wonder how should I tell them about the issue.. hopefully I can get the noise to appear when I drive it there.. Mine still got some powertrain warranty left.. if it involves transfer case and third member/axle all that.. will it be covered by the warranty..? Just curious.. thanks..

 

Hey folks, I just wanted to give you a quick update.
Last week, Toyota replaced my transfer case cap in hopes of stopping the high-pitched squeal. So far...NO SQUEALING! I will let you all know ASAP if it comes back.

 

I've got the same problem on my 2018 4Runner... drives me nuts. Doesn't correlate with anything. Would like to know if the new transfer case cap works.

 

My mechanic at the Toyota Dealership did some research with the engineering department at Toyota Corporate which is where he learned about potential issues with the transfer case caps. I will let you know ASAP if the noise returns. It has been hotter than hell in my area lately (which is usually a trigger) but nothing yet.

 

Thanks for the update Nick.. I took mine to the dealer and they kept saying it's the brakes so I had to take it back. If the transfer case caps did the trick I'm gonna just bring it in and have them replace that without messing with all the diagnostic bull again.. Thanks again..

 

I took my 4runner into the dealer on Thursday morning of this week and they had no idea what might be causing the noise. Ironically, I couldn't reproduce the noise on the way there nor has it returned since, although I am sure it will eventually.

 

A friend of mine, who owns a Honda dealership, talked to his techs, one of whom has a dad who is a Master Tech at Toyota. That gentleman said the sound could be caused by air flowing through the side mirrors. I haven't heard the sound in 5 days, after 6-12 months of it happening all the time, so who knows... but if the transfer case cap doesn't solve your problem, try taping the side mirrors down tight as an experiment.

 

That's interesting. The noise my 4Runner made didn't slow down or quiet when coming to a stop, which if it was airflow, I would think it would gradually go away when slowing down. Anyhow, we are going on 2 1/2 weeks now with no high-pitched noise. I'm very hopeful it was the transfer case cap!