Washing machine has small leak
 

1996 Kenmore 90 series
Wife noticed the rung under the front feet of the washer was wet. I let the area dry and put 20-25 gal water in the basket (no leak) then spun it dry.. No obvious leak. I tipped the unit back just past the balance point and looked underneath for water.

There was a drop of water hanging down from the motor and a lightly oiled moist area around the center of the transmission. The wiring harness was wet but the pump inlet and outlet hoses were dry. Pics at:
https://app.box.com/s/yv3vf9qpj6r081dfkpwyveyjytcfyplg

After I set the machine back down, around 4 oz of water puddled in front of the machine. I just looked at the exploded parts diagram and see under the tub "Gasket, Centerpost Switch" which I presume I must replace. Does this sound right? Do I need a special wrench to remove the basket?
Bob