Why is my clothes dryer squeaking with a pitched noise while drying?

Squeaking normally indicates a problem with either the teflon gliders (replace gliders), with the plastic rollers (replace rollers), or with the drum bearing (replace dryer). You can not economically replace the drum bearing.

You have to do a little research here.

To check what is going on in your dryer :

Remove the rear panel, and have a look as to what is going on.
Check the drive belt : is it frayed?
Is the drum running against something?
Does anything look lose or broken?

Please be careful : do not touch anything while the dryer is connected to the power.

If you can not find anything, remove the power - take the power cable out of the socket and put it on to the ground.
Note down how the belt is connecting the drum and motor.
Remove the belt (by taking away the tension from the belt this is easy).
Spin the motor a couple of times by hand, as fast as possible. Is it running freely? No squeaking?
Spin the (empty) drum a couple of times by hand, as fast as possible. Is it running freely? Is it squeaking? If so check the teflon "gliders" between the drum and the door window, or the plastic rollers holding the drum horizontal at the front.
If these are OK, than check the drum bearing.

Of course you can also come back to the board and discuss your findings!
If necessary contact me by private mail (click on my handle and follow instructions) to draw my attention.

Success !

:)