When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
This is the transmission. The leak is probably from the main seal between the engine and the transmission. Make sure your PCV system, flame trap, etc. is not plugged up so as to be causing excessive pressure on the main seal (among others.)