65 Barracuda - 904 Transmission Oil Leak
I replaced mine bout a month ago. 904 318 69 barracuda. Pull all the linkage out of the way and pry the old one out with a small 4" or so flat blade screwdriver. You should feel 2 steps, clean em real good. Slide the new seal on to the shaft and tap it down with a deep socket, the weight of the socket is plenty for tapping it in tight. Just watch out you don't start it crooked.
Under $6 shipped
http://www.ebay.com/itm/Timken-8609-Shift-Shaft-Seal-/390889681770