Squealing noise while driving!

[TracSport]

Every once in a while at random times while it's colder than 30 degrees, I hear a loud squealing noise coming the front of the truck which ends up really squealing from the back. When I open up the back window, you can really hear it coming from in between the bed and cab. At first I thought it was the belt which is new as of this past summer so I sprayed some belt spray on it. It does not squeal in park, only while driving. Has anyone come across this weird situation? It's really embarrassing , almost more embarrassing than my horn issue!
Thanks.

 

[glfredrick]

It almost sounds like your belt is slipping badly when the fan kicks in (automatic fan clutch on Explorers).

I'd change the belt and see what happens.

I'd also check the power steering unit to make sure it is filled properly.

Try to duplicate the noise with the hood up so you can isolate the cause. Sometimes a mechanic's stethascope can be helpful. It lets you hear a bad bearing in a water pump, alternator, etc.

A couple of things I'd check...

1. Is it RPM related (speed up when you press the throttle in neutral)
2. Is it drivetrain related (not dependent on engine speed, but vehicle speed)
3. Does it happen when you are turning, pressing the brake pedal, etc.?
4. Is it on acceleration or deceleration -- or drive coast at speed?

If it isn't the engine, it could be a bad bearing in the 4x4 system or something.

 

[TracSport]

It has to be speed related. Like I mentioned before, it will not squeal when in neutral, even over 3000 RPMs (that's another question, everyone says there is rev limiter). The squealing happens when I'm going over 20 mph on acceleration and de-acceleration to a point and when colder than about 30 degrees but this does not happen all the time. It almost does sound like it's coming from the drivetrain. The belt feels snug and I put belt dressing on it to help it from slipping and drying out.

Thanks for the reply!

 

[billz260]

I have a simular sound, but i'm pretty sure it's been with the truck since I've had it (12 years). Whenever it's cold, it sounds like a belt but i don't think that's what it is. I suspect cold bearings in the alt or water pump, but it almost always goes away as soon as you put it gear and drive off.

EDIT:Sounds like we have different issues.

 

[TracSport]

After driving around this afternoon, the noise is most noticeable when driving at a constant speed or letting off the gas. The minute I hit the gas, it goes away until I let off the gas again. After a stop, such as at a stop sign, it might not even make the noise until a later time. Very weird. I still can't reproduce the sound in park or neutral.

 

[IZwack]

Quite obvious its drive train related -- probably a bearing in either the transmission or the rear differential -- check for play at the rear differential's pinion flange.

 

[svaby]

Ah im glad i seen this i have the same sound in my 02 ST and it's only when it's cold and when i am on the gad not off of it... seems like it's comming from somwhere up front to me when i try to listin to it like behind the dash it seems so damn close...

 

[TracSport]

My squealing has gotten so loud at times, I know for a fact it's coming out the rear end. I also took it in for a mechanic to hear it and they believe it's the U joints in the rear end. I still need to take it back so he can keep it for the afternoon and actually get under the truck to look.

 

[Benjamin265]

I'm betting you have a 5-speed. It sounds like your throw-out bearing.
Mine started making the noise yesterday on my way home. By the time I pulled in my driveway (35 miles) my clutch went to the floor from wearing out the fingers..