Squeky Dryer

My sister dyer had this annoying squeaky noise when its been used. I have it opened, looks every parts and it seems okey but maybe burnt out just like the bulb. Anyway, I applied some W40 on the pulley (where the belt is located, rear bearing drum, the hole where the bearing goes in and it works for a while not until it reach the 3 minutes marked where its started to squeak again. What could be the problem Pros. Any suggestions?
Thanks again for your immediate respond.

Usually on these GE models that kind of problem is the rear bearing/drum sleeve. You can see the parts on this diagram here.

http://www.appliancepartspros.com/drum-parts-for-ge-dhdsr46eg1ww.html

You will need to take out the drum to fix it, you do this by taking off the top, then the front and then releasing the belt.