I have a chirping or bearing sounding noise, that I am trying to isolate on my daughters college car. Sound varies with RPM.

you're on the right track, removing the serpentine belt and manually rotating/ spinning the pulleys listening for a dragging, or grinding. If its very bad you may even see a outward movement. hope this helps!

If is a serpentine belt, take it out and check the belt tensioner. some of them have a screw that allows for tightening/loosing the belt. Sometimes it looses some bearings and it could chirp.

a noise from a diff are , normally a high frequency harmonic sound while driving is from diff pinion bearings
if you decelerate and you get a noise normally as a low grumble ( low drumm noise )to a frequency noise is again the diff pinion bearings
you can distinguish the noise from power on to deceleration
the noise can be most noticeable with a slight load ( 2 people travelling at a steady speed say 60- 80 klm/hr) as a steady but harmonic pitch variation
the noise varies as the load is transferred from the bearing immediately behind the pinion gear to the bearing immediately behind the drive flange or in your case driven gear from the gear box
it is caused by a slight movement of the pinion which varies the correct mesh with the crown wheel , resulting in the whining sound
sorry but noise sounds are very hard to describe

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Speedometer cable may have a broken stran of wire causing it to squeak when it turns.

There are many possibilities that can cause car to make noise.

It's actually from where the noise is coming from. Front end or rear end. From engine area or from inside the steering or from brakes.

There is N-number of possibilities for the car to make wierd noise or any other kind of noise.

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For step by step troubleshooting this problem, I suggest you to refer the help links mentioned below. Its a complete solution with proper explanation to identify the cause of problem: ------

Click the link below: -----

Car makes clicking noise?

http://howtobyme.blogspot.com/2011/11/car-makes-clicking-noise.html

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Car makes whining noise like driving on rough pavement?

http://howtobyme.blogspot.com/2011/12/car-makes-whining-noise-like-driving-on.html

------------

Chirping Noise From Car?

http://technoanswers.blogspot.com/2011/11/chirping-noise-from-car.html

----------------

What are the possibilities for Clicking noise in car?

http://technoanswers.blogspot.com/2011/11/what-are-possibilities-for-clicking.html

--------------

Squealing at start up on car?

http://technoanswers.blogspot.com/2012/01/squealing-at-start-up-on-car.html

--------------

Chirping sound coming from engine?

http://technoanswers.blogspot.in/2012/01/chirping-sound-coming-from-engine.html

-----------

Vehicle making Clunk Thump Thud noise?

http://howtobyme.blogspot.in/2012/03/vehicle-making-clunk-thump-thud-noise.html

------------

4X4 Truck makes roaring noise in the front end?

http://schematicsdiagram.blogspot.com/2012/01/4x4-truck-makes-roaring-noise-in-front.html

--------------

Heater makes clicking noise under dash on Ford Explorer?

http://technoanswers.blogspot.in/2012/01/heater-makes-clicking-noise-under-dash.html

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Clicking noise under dash and front defroster not working?

http://technoanswers.blogspot.com/2012/01/clicking-noise-under-dash-and-front.html

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Car Brakes Making Noise?

http://repairhelpcenter.blogspot.com/2011/12/car-brakes-making-noise.html

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Car Alternator making noise?

http://repairhelpcenter.blogspot.com/2011/11/car-alternator-making-noise.html

-----------------

Car Alternator Bearing Makes Grinding noise?

http://repairhelpcenter.blogspot.com/2011/12/car-alternator-bearing-makes-grinding.html

----------------

Engine makes noise and Cooling Fan belt Breaks?

http://howtobyme.blogspot.com/2011/12/engine-makes-noise-and-cooling-fan-belt.html

--------------

Vehicle Makes Clicking Sound While Taking turns?

http://schematicsdiagram.blogspot.com/2011/12/vehicle-makes-clicking-sound-while.html

-------------

ABS light comes on and Car makes Grinding noise?

http://repairhelpcenter.blogspot.com/2012/01/abs-light-comes-on-and-car-makes.html

-----------

These will help.

Thanks.

There are many possibilities that can cause car to make noise.

There is N-number of possibilities for the car to make thud noise or any other kind of noise.

---------

For step by step troubleshooting this problem, I suggest you to refer the help links mentioned below. Its a complete solution with proper explanation to identify the cause of problem: ------

Click the link below: -----

Vehicle making Clunk Thump Thud noise?

http://howtobyme.blogspot.in/2012/03/vehicle-making-clunk-thump-thud-noise.html

------------

Car makes clicking noise?

http://howtobyme.blogspot.com/2011/11/car-makes-clicking-noise.html

--------------

Car makes whining noise like driving on rough pavement?

http://howtobyme.blogspot.com/2011/12/car-makes-whining-noise-like-driving-on.html

------------

Chirping Noise From Car?

http://technoanswers.blogspot.com/2011/11/chirping-noise-from-car.html

----------------

What are the possibilities for Clicking noise in car?

http://technoanswers.blogspot.com/2011/11/what-are-possibilities-for-clicking.html

--------------

Squealing at start up on car?

http://technoanswers.blogspot.com/2012/01/squealing-at-start-up-on-car.html

--------------

Chirping sound coming from engine?

http://technoanswers.blogspot.in/2012/01/chirping-sound-coming-from-engine.html

-----------

4X4 Truck makes roaring noise in the front end?

http://schematicsdiagram.blogspot.com/2012/01/4x4-truck-makes-roaring-noise-in-front.html

--------------

Heater makes clicking noise under dash on Ford Explorer?

http://technoanswers.blogspot.in/2012/01/heater-makes-clicking-noise-under-dash.html

---------------

Clicking noise under dash and front defroster not working?

http://technoanswers.blogspot.com/2012/01/clicking-noise-under-dash-and-front.html

------------------

Car Brakes Making Noise?

http://repairhelpcenter.blogspot.com/2011/12/car-brakes-making-noise.html

---------------

Car Alternator making noise?

http://repairhelpcenter.blogspot.com/2011/11/car-alternator-making-noise.html

-----------------

Car Alternator Bearing Makes Grinding noise?

http://repairhelpcenter.blogspot.com/2011/12/car-alternator-bearing-makes-grinding.html

----------------

Engine makes noise and Cooling Fan belt Breaks?

http://howtobyme.blogspot.com/2011/12/engine-makes-noise-and-cooling-fan-belt.html

--------------

Vehicle Makes Clicking Sound While Taking turns?

http://schematicsdiagram.blogspot.com/2011/12/vehicle-makes-clicking-sound-while.html

-------------

ABS light comes on and Car makes Grinding noise?

http://repairhelpcenter.blogspot.com/2012/01/abs-light-comes-on-and-car-makes.html

-----------

These will help.

Thanks.

If it is a rattling sound the starter may be loose, the starter bendix gear might be damaged.

If it sounds like a fan, it is likely the cooling fan.

If it is squealing, it is the serpentine belt. The idlers may be worn, their bearings may be dry- they make a chirping sound at slower speeds when they are dried out. Replacement is the best option.

Air pumps can sometimes make a thumping sound, and if certain emissions valving rusts through, it can be outright exhaust noise.

If it is a high pitch whine, that is usually the alternator. It is not a good sign when they begin to whine. Alternator bearings can also fail, and the sound varies.

Water pumps and fan clutches can also fail and they tend to make softer sounds. These can be checked by checking for radial play in each item with and without serpentine belt tension applied.

where is it coming from exactly can you hear it from in side the car or outside or even both

IF YOU HEAR RATTLING NOISE IN SUPER CHARGER.YOU HAVE WORN DRIVE MECHANISM LIKE LOOSE ROTOR SHAFTS OR WORN ROTOR SHAFT BEARINGS.