transmission quesstion/ Speedometer

[Racin_jason]

I had to replace the speedometer cable on the truck and had begun to pull it out this weekend. When I crawled under the truck to remove the cable from the trans I noticed that it was leaking, what seems to be the sorce of my trans leak from the attachment point that houses the speedo-gear. I was wondering if anyone would know where to look for such a part or what the name of the parts that i'm looking for are called. I'm not planning on doing this until next week or even after cause I did already have a trans-filter replacement to do aswell.

thanks yall