I hope someone can help me. I dropped the trans. pan to change gskt. on my 04 automatic f150, only to find a part lying in the pan. I do not know what it is. It is yellow and shaped like a mushroom with stem and has an o ring, like some kind of plunger. Trans. was leaking, for that was the reason for changing gasket. I am new to this forum, and I hope someone can help me.

 

Pretty sure this is a plug left over from the factory and is nothing to worry about. Shows that the pan has never been dropped before.

 

Thank You Canstacker, I thought I was losing my mind. I went to Advance auto and they googled it by discription and you are correct. Thank you again.