727 shifter shaft seal

There is a special tool that allows you to replace the seal in the vehicle. Once you have done it a couple times its a 10 minute job.
You will need the pan off to replace the inner seal (o-ring). it requires you remove the c clip and the throttle pressure lever will have to be pushed back up when you reinstall.
Most of the time the inner seal is ok, its the main seal that causes all the trouble. I consider this seal a normal maintenance item. If its not leaking its just a matter of time.