Transmition Problem v8-s10

I have a TH-350 Trans in my 85 s10... and it leaks tranny fluid from the The speedometer cable area.. Can anyone tell me what part i need and how much it would cost to be fixed.. Ide really appreciate it thx a lot

there is an o-ring that seals the gear. i can't give you a price but probably cheap.

there is also a seal that rides on the speedo gear itself. they are pretty cheap to.