[RichardLee]

I began to notice a squealing noise related to vehicle speed (not engine speed) a few weeks ago and I thought I fixed it by spraying some brake silencer on the front rotors (it seems to be coming from the front) but now it's back and worse than ever.

The noise is regardless of gear (when I put it in neutral while the car is rolling it has no effect) but the interesting thing is that it almost completely goes away when I accelerate. As soon as I let off the gas it appears, and as soon as I press the gas pedal even a little, it's gone.

Also, I'm ruling out the brakes because braking has absolutely no effect on the noise, but sometimes when I turn the wheels slightly, this does affect the sound. Sometimes it almost goes away and sometimes it seems to make it worse.

I had a mechanic ride around with me today and he suspected some loose piece of plastic stuck somewhere (seems like a strange diagnosis), so I checked everything out and I can't seem to find anything like that.

I plan to bring it to a shop tomorrow or Saturday, but first I'd like to know what I should be letting them do.

Can anyone think of something that could make a squealing noise (almost like a loose belt or bad bearings) that is independent of engine speed or transmission gear, that goes away under acceleration? It's getting louder and I'm afraid something is going to give.

Any help at all, even a wild shot in the dark, would be greatly appreciated.

Thanks,
Ric

[gdevita]

Sounds like your drive shaft needs lubing!!! Same thing happened to mine...a little chirping noise only while your "coasting", right??? Check out this link and report back with your results. Best of luck Toyota Maintenance: Lubrication Points

[brian2sun]

Yea, I also suggest your u-joints/driveline need to be greased.

[JohnsD90]

If that's not it, your problem may be your rear diff, if it is something wierd wrong with it please post your results.

[rdgt4r]

Belts, especially that notorious A/C idler pulley that squeals. Do like others have mentioned too.

[MillerPKA]

I would also check your power steering

[Jed]

It would help if you could locate the general area where the sound is coming from. My first guess would be drive belt or pulleys. An old trick is to put a little soap on the working surface of the belt to act as a temporary lubricant. You can carefully do this by hodling a bar of soap up under the moving belt (gotta be careful not to get your fingers in the belt) for a few seconds with the engine idling. If you do that and the noise goes away, then you know it was related to the belt.

At that point, I'd probably check the tensioner and condition of the belt itself. If the belt is worn, definitely replace it. But also make sure that the newly installed belt doesn't have too much deflection. You can usually test this by pressing firmly on the belt between two pulleys and eyeballing the amount that the belt can be pushed with your finger. Generally, pulleys that are about 12 to 18 inches apart should have about 1/2 inch deflection. Toyota probably has a spec for this, but I don't know it off hand.

If all that checks out, then you should look at the alignment of the pulleys. Whenever you have belt noise that won't go away no matter what you try, the problem is usually one pulley that is just not in perfect alignment with the others. You can check this by using a large straight edge and putting it across all the pulleys (in pairs of two, of course). They should be aligned perfectly.

Damn, all that typing and I'm not even sure if your problem is belt related. But if it is, now you have a few things to check out. Good luck.

[RichardLee]

Wow. Thank you everyone who is offering some help here. I really appreciate it.

I saw the first response about lubing the drive-shaft about an hour before work, so I stopped by a shop that's on the way and had them do it. (Merlin, and they did it for free, which I thought was pretty cool of them) On the drive from there to work, I could still hear the noise, just as bad as ever. I'm thinking either I can rule that out or maybe there's something they missed.

About the belts- could a belt really only make a noise that correlates with vehicle speed? It seems to me that all belts are directly connected to the engine and any sound they make would fluctuate according to engine speed. I'll check them tomorrow anyway, but they are all new (except the TB, it's original with 98,000 on it) so I am doubtful they are the culprit.

I plan to bring this back to the same shop that hooked me up with a free lube job today, despite it being unsuccessful.

Can anyone think of anything else I can check for myself first, anything I should mention to the mechanic, or anything I should NOT let them charge me to do?

Thanks again for the help you guys!

[kball]

"seems to be coming from the front" and "related to vehicle speed not engine speed" I'm going to guess front wheel bearing.

[rdgt4r]

Yeah, we still need more information really anything further helps.

[RichardLee]

Quick question- When a driveshaft is lubed, does the grease take a while to work it's way in and do it's job?

I had the lube job around 3:15, and drove about 2 miles to work from there, still hearing the noise. Drove about 2 miles back from work around 8:30, still there. Drove about 10 miles to go see a movie tonight and it was still there on the way, and even in the parking lot after the movie got out around Midnight. I drove about 10 miles home again and now it's completely gone. I turned off my heater and stereo and opened the windows because I couldn't believe it, but the noise really is gone.

I'm not too excited yet about this, because it has subsided before, only to return worse. The only way I'm thinking it will stay gone is if it were simply that the drive-shaft needed lubrication and it took driving 15 miles after the lube job for it to work. If that's the case I'm going to be one happy camper... I mean come on, how often is problem literally fixed for free at a shop?

So that's where I'm at. Thanks again to everyone who offered some help. I'll keep you all updated.

More info about noise (as requested)-
Related to vehicle speed
(Pitch of squeal never actually changes, just becomes louder)
If vehicle is stopped, engine sounds strong and clean, even at high revs
Completely stops under 24-25 mph
Has no effect on driveability
Is worse after a car-wash (washed it today with the undercarriage wash and it was really bad immediately after)
Comes from somewhere in front of and below me
Braking has no effect
Turning seems to have an effect, but since I normally slow down to turn it's hard to say
Accelerating makes it stop, but as soon as I let off, it returns

...that's about all I can think of. If it comes back is there anything else I should be listening for?

[rdgt4r]

Well yes the grease needs to be worked in sometimes depending on the instance. i just wonder if it was the yoke, u bolt or what. But if its gone it should stay that way. Remember lubricating is part of maintenance, I do it every other oil change if not more depending on the type of driving i have done.


But with all that said I still think its a belt or pump or pulley of some sort, especially what you described.

[RichardLee]

Originally Posted by rdgt4r

Well yes the grease needs to be worked in sometimes depending on the instance. i just wonder if it was the yoke, u bolt or what. But if its gone it should stay that way. Remember lubricating is part of maintenance, I do it every other oil change if not more depending on the type of driving i have done.


But with all that said I still think its a belt or pump or pulley of some sort, especially what you described.

I will definitely begin lubing my whole drive-train regularly now. I just need to get a grease gun to add to my oil change kit.

The guy at Merlin said they hit the 5 'grease points' (his term) that 4Runners have. These are zerks? I've got some reading to do...

rdgt4r, could you explain exactly how a belt or pulley could behave in such a way? I'm here to learn, so if you wouldn't mind explaining that a little, I'd really appreciate it.

Thanks again for the help,
Ric

[rdgt4r]

Originally Posted by RichardLee

I will definitely begin lubing my whole drive-train regularly now. I just need to get a grease gun to add to my oil change kit.

The guy at Merlin said they hit the 5 'grease points' (his term) that 4Runners have. These are zerks? I've got some reading to do...

rdgt4r, could you explain exactly how a belt or pulley could behave in such a way? I'm here to learn, so if you wouldn't mind explaining that a little, I'd really appreciate it.

Thanks again for the help,
Ric

Heres a great link for maintenance, more specifically the zerk fittings on the driveline 4Runners.org - Lubing Your Driveshaft

Its strange in that it almost could be a number of things causing this sqeak/squeel. If you wash a car underneath especially the front of the motor area you will get a squeal from water on the belts but that usually goes away shortly there after.

if a pulley's bearings are on their way out they will squeak, so will belts if they are worn down or not tight enough.

When your turn it makes more noise im guessing? could be the PS pump.

There is so much going on its hard to say without hearing it and isolating it more.

I hope it was the drive line and it sounds like its solved, and thats all that matters. Keep us posted on this!

[RichardLee]

The Saga Continues...

After the free lube job, I thought I had noticed the noise at least significantly improving. Then, after a couple days, it was back just as bad as ever.

I checked the belts, WD-40'd the pulleys and tried some belt dressing to see if it would temporarily help. No luck.

I brought it back to Merlin, where they took the time to pull the driveshaft. They found that an entire section of it was completely dry, so they put 'massive amounts' of grease on it and now the noise it gone. Hopefully this time it will stay that way.

My question is this- how can a sealed driveshaft go completely dry? Why did the quick regular lube job not cover everything? Is this a normal maintenance issue or is something wrong to cause such a problem?

Thanks again for all the help,
Ric