oil drip on a 2.7 liter

Hello, We have an irritating oil drip coming from the passenger side bottom of our 2.7 liter 2006 tacoma. The drip is coming from the front / side area and directly behind the crank pully. It looks like it is seeping from a small oval shaped plate like assembly that has 1 bolt holding it into the block. Does anyone know what is behind that oval shaped plate? Is this something we could possibly repair ourselves? We checked that bolt and it's tight but we're not confident about taking it out because we have no idea what is behind that oval plate.
Thank you in advance for any advice as we truly don't have a clue !
Respectfully,
Tom

 

Sounds like the front main seal is likely the culprit. Part number for replacement is 90311-48031

The crank pulley will need to be removed to gain access to replace the seal