WTF IS THIS HUMMING NOISE?!

So I noticed a humming noise that seemed to be coming from the front end well driving 45-50 mph and then nothing until 70+ mph in both 2 wheel and 4 wheel drive. So I thought oh great, it's my wheel bearings again.

Well, I just replaced both sides and guess what?! It still does it.

I could really use some help trying to figure out what the issue could be.

Facts about my truck
2007, 4 cylinder, 4x4. Icon coils up front set for 2.75", add-a-leaf in the rear. 285/75/16 a/t tires.

My truck didn't make this noise until I installed the all pro apex bumper, and all their skids. Could this noise really just be wind noise? Seems doubtful as loud as it is.

This forum has been an invaluable source of knowledge for me, I really need some real suggestions. Thank you in advance!

 

If you want to test the wind noise theory, tape some cardboard over it and go for a drive. Also, when you hear the noise, put the trans into neutral and coast and see if you still hear it.

 

It still makes the noise while in gear, and in neutral. I suppose I could try taping the card board over the openings on the bumper

 

There's a good chance that you're hearing extra tire noise because of all that extra weight. Try inflating to higher psi. If that's it and you have to go above the tire's max pressure to reduce the noise, then it's time to get higher load rated tires. Just one of many possibilities.

 

I'm currently running at 45 psi I'll try brining the pressure up though, time for ultra rough riding.

Does that make sense where it's only obvious at certain speed ranges though?

If this works I'm going to kick myself for spending the time and money on those damn wheel bearings

 

Take the bumper and skids off and see if it still makes the noise. Only way you could truly rule them out.

 

Rockersnapper might be right. Have you rotated your wheels lately? Fronts might be cupped and need moving to the rear.

ETA: suggesting higher psi was for diagnostic purposes, not a solution

 

http://www.tacomaworld.com/forum/2n...nt-differential-bearing-vibration-thread.html

Sure it's not this?

 

Any chance the skids are vibrating and acting like a drum??

 

Try taking a video and post it so we can hear the noise.

 

Im getting the same humming in my '13 AC...Unfortunately its not coming from my chick......

 

Holy smokes all of you are awesome, I just did a 300 mile trip today and well I guess I'm slightly retarded.

A few weeks ago I stopped at a gas station to air up my tires to 45 psi, the air compressor there was garbage and I got tired of spending $1 a tire for 10 psi. So I only did the fronts, a week later I rotated my tires when I changed the brakes but spaced on bringing the now front tires to 45. They were at 33 psi before I started my trip, brought them up to 45 and the only noises I get now are wind and normal tire noise on the highway. I feel like an idiot now.

But once again thank all of you for being a kick ass group of people and giving any advice!

 

Aloha from Hawaii. It's been a few years since of logged on to the site. I too am searching for an answer as to what's causing a low pitch humming noise on my 06' PreRunner DC. The truck went in for service and a safety check in early February. I failed the safety due worn tires. Went to Costco and replaced all 4 tires to pass Hawaii's Safety Check. Nothing special - I went with Michelin X-Radial LT2 All Seasons (P26570R16) to replace the worn Firestone Destination AT. The truck also went to Firestone for it's regular lifetime alignment check a few days later. By the way, the service shop recommended cleaning the throttle body, injectors, and changing plugs which I should be doing soon. They also recommended new brake pads and resurfacing the rotors - changed out the rotors and pads today. Truck has just over 102,000 miles.

Almost immediately after replacing the tires, I notices a low pitch humming noise coming from the front end. The noise is noticeable at all rolling speeds and increases with higher speeds. At first though it was related to RPMs but quickly dispelled that as there was no change to the noise when I revved the engine in gear or in neutral. So I though, okay, its tire-road noise. But I quickly noticed the "normal" tire noise in the background that I was used to. The noise is most noticeable when the windows are up. A couple of days ago, I noticed something I didn't notice before. The noise goes away when i am making a right-bank turn where the steering wheel is turned at least 45+ degrees to the right. The noise only occurs on straightaways and when turning left.

So now I'm thinking wheel bearings, given the mileage on my truck. But before I go out and spend an arm and leg getting the front wheel bearings replaced, I want to make sure I ruled out everything and anything else. Tires are running at the MFG recommended 29 psi. I''m currently not carrying any loads. I've yet to experiment with tire pressure or checking for possible wind-tunnel effects, but would either of those make any difference - especially given the fact that the noise goes away when making right turns only?

Any ideas? Thanks in advance.

 

When you drive down an empty road try quickly weaving left / right a few times. See if the noise Comes and Goes and if so when does it happen/go away.

Also, you can find a nice long building wall (i.e. the back of a large store in a mall) that you can drive close to. Drive with your windows down back and forth and see if you can hear the noise better. Perhaps have a helper stand outside and help listen as well. Let us Know ...

 

Actually, my daily drive involves a couple of S turns. The sound always goes away on the right turns and always reappears as soon as I turn the wheels to the left or going straight.

Haven't had a chance to drive close to a long wall yet. However, yesterday I changed out my rotors and pads. One thing I noticed after removing the old rotors and before installing the new, when I spun the spindle by hand, the right side was practically quiet, while the left side appeared to have a metallic noise - more like a metal on metal sound.

 

you could rotate the tires just too be sure it's not a bad tire belt - but I'd put my money on a front bearing ...

 

Already did 1 tire rotation since Feb. So I know its not the tires.

 

It's the front left bearings going bad (in my opinion) To check, jack up that side and give the tire a spin. ANY noise is going to indicate bearings. Also, try moving the tire from side to side while holding it at 12 and 6. Any play here is also bearings saying goodbye.

 

I had the same issue in my '06 Tacoma TRD. 105,000 miles. It was a front wheel bearing. I replaced both. Noise gone.