Squealing noise on start up.

I opened the back acess panel and started the dryer. Looking at the motor and idler pulleys it was obvious by the frequency of the squealing noise that it was coming from the idler pulley.
I pulled the retainer clip and tension spring from the idler pulley and removed it. I applied some grease to the shaft and reinstalled the idler pulley.
The squeal was gone confirming that the pulley bushing was dry. I ordered the new idler pulley and when it arrived the next day I cleaned the grease off of the shaft and installed the new idler pulley. Problem solved.