when drum is turning it has a very loud squeal. Do I need to only replace the bearing?
Here are your parts
http://www.appliancepartspros.com/partsearch/modelsearch.aspx?model=fez831as1
Do I need to only replace the bearing?
Yes that is the most common problem with this type of drum mounting.
Could be it just needs cleaning and re-lubing with high temperature grease.
Also when removing the rear cover (Item 6 in Section 1) be careful as the ball bearing (Item 5 in Section 1) likes to take off and hide once it is released.
Other possibilities would be the front glides or the idler wheel