There will be a lot more oil sprayed around inside the cabinet wall. You may get away with just changing the lower oil seal if lucky. It may have also worn the top seal on the gearbox which prevents water getting down the agitator shaft in to the gearbox. You won't know until you open the gearbox and see if water is in the oil. It may also have worn away the bronze bush bearing through which the lower gearbox shaft passes. Too much wear will allow too much oil down the shaft and a new seal won't stop it leaking. Really not a job for DIY.
Linoln Appliance NZ
November 2013