Help me diagnose this faint howling noise

Hi all,

I'm still relatively new to my 2nd hand Tacoma so I'm still finding things that seem odd.

I was driving with the music off the other night and noticed a faint howl that seem to come from the rear passenger side of the vehicle. At first I thought someone had left the window cracked or something but that wasn't the case.


I never noticed this on any of my test drives nor have I noticed it in previous weeks with the radio off... so this is probably something that's just starting out. Here's some observations I've made so far:

• It consistently comes on around 50km/h (~30 mph) and doesn't appear to go away until I drop below that speed. At higher speeds if its still there, it gets drowned out by the sound of wind and tire roar.
• The noise doesn't get louder or change pitch as I go faster
• The noise doesn't get louder or change pitch with engine revs
• The noise isn't affected by braking
• The noise is apparent regardless of whether I'm accelerating decelerating
• My entire cabin is kinda vibey beyond 110km/h (~70mph)

The previous owner had to replace the passenger side leaf spring because it snapped on him going down the road. It is a brand new unit.

What do we think? Bad wheel bearing(s)? Differential? Anything I can do to check or do some preventative maintenance in this area of the truck?

 

When was the last time it was aligned? One cause could be that your Toe is off on one of your tires so it drags a bit, causing the howl.

 

I have the same issue with mine. I notice it more often when it's windy or when I have my road bike on the mount in my bed (it sticks up about 4-6" above to top of the cab).

I always assumed it was just an inadvertent sideaffect of the cab shape or something with the weatherstripping in the door?

 

Wheel bearings

 

Is it only when its windy? I hear noises with the wind sometimes if its blowing pretty good and I'm headed in the right direction at the right speed. Somtimes from the front windsheild, and if I'm hauling stuff, sometimes from the back. I just shake it off, it doesn't happen very often.

 

If it wasn't wind, I would bet it is one of your wheel bearings.

 

Yeah I usually only notice it when its windy. Very rarely if I'm hitting 85+ going down the road I'll hear it if its not windy.

I don't think its wheel bearings. I've had that issue before and this is a different sound. It also sounds like its coming from the upper passenger door frame to me. I never fails either, when someone is sitting over there I never hear the sound so I can't have them see exactly where its coming from.

 

Do you have any snow or ice accumulations on the roof, hood, windshield area, bumper or even the front lower control arms? - Any snow or ice on those areas for me this usually results in some low level howling or whistling noise.

 

For me no, I'm down is SE Texas. I've noticed it all year round, with and without my bicycle in the back (although it happens more with the bike mounted in the back). I think its just a function of design and something causing the airflow over the truck to whistle a bit.

 

Try opening a window on the drivers side a couple inches. IF it goes away I'd say it's an air leak. check/Clean/grease the door seals, check for doors not closing tightly, etc.

 

Howl like wind or more of a groan/ vibe sound? These days my default guess is needle bearing because I haven't fixed mine yet.

 

Do you have this noise? I made a post about some vibes and I get some of that howling you're saying and some members have said needle bearing also...from the drivers side front tho

 

The needle bearing noise is similar to tire tread humming. It's most noticeable around 30 - 45 mph regardless of terrain (dry road, rain, snow - offroad, other noises can drown it out)

OP doesn't say 4x4 or not but if so, if the noise goes away immediately when you engage 4x4 it's the needle bearing.

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

Yes, I have the noise.

 

Not sure about the original guy but for me its more a howl like on a really windy day you're in the house and you can hear it outside. Highly doubt its a bearing issue at this point but I could be wrong.

 

Get your truck up to the noise speed on a clear straight empty road then do a hard swerve left then right and repeat. IF the noise comes and goes when you only pull to one side it's probably a bearing.

 

There's a flap in the back, behind the seats that allows the air to run/airbags to open and not pressurize the cabin. A couple people on here have complained that it was too noisy and opens unnecessarily. http://www.tacomaworld.com/forum/2n...b-rear-pressure-vent-research-experiment.html

 

Also could be that it is blocked preventing the air from escaping and causing a positive pressure in the Cab. Excess pressure then pushes on the window and door seals and leaks out with the air noise.

 

i have the same noise. been there since new. noticed it in other tacos as well. think its just a harmonic vibe.

 

So get her up to ~80-90mph...could throw two jokes out here, one about going back to the future, and the other about hearing a few other noises as the trucks cartwheels sideways haha.

I do get your point though. It is slightly more noticible with a crosswind, which would require more control input to keep in a straight line. If I find a stretch of road I can do this on and I might give it a shot

 

Ok, let's take this in s new direction...... And is this after you have eliminated a wheel bearing issue.

Tacomas are known for wind noise caused by hood gaskets, fish a piece of 1/4 od plastic tubing through the rubber gasket between the hood and the radiator support and above the headlights. Both my '13 and my '14 did this. The wind will force the stock rubber gasket down and make it whistle. You could probably blue tape the hood gap in the front to test it

Tacomas from about '08 and up have a TSB regarding howling rearends. This typically starts around 45 - 60 mph especially down hill with your foot off of the pedal. My '14 does this and it's worse with more weight forcing you forward like a trailer.

Some Tacomas are known for windshield whistling, tape up your windshield trim with blue painters tape and go for a ride.

I've head that the roof racks can cause this too. Fortunately for me I don't have one of those butt ugly racks on mine.

I hope this gives you a few new ideas, I'm anal about that kind of stuff.