Ditto the others replies, I don't think I've ever dealt with a good old KD-anything that was leaking from anyplace besides the pump seal. If it's gotten noisy as well, the leak may have damaged the bearings. They put a slinger ring/disc on the shaft, but it's not effective enough for more than a drop or two now and then. You can probably pull the motor apart and replace the bearings by themselves if you're so inclined -that may well restore the motor to near new. There's nothing else that really wears out on the motor circuit besides maybe the start relay or cap (don't recall which they used).
This design, like the old GE washers with the great big dry clutch under the pump, was not so great. Even Kitchenaid with their commercial lineage and excellent quality doesn't last forever. One of the few advantages of the old GE "Sidewinder" two-wire DW pumps, though those were prone to stuck seals in vacation homes that sat all summer or winter. They had so little starting torque, they'd just sit there and hum...
p.s. they're not known for "quiet", even when they were new. they make all sorts of humming and chugging noises, depending on how far they've filled or when draining... there was never a doubt they were doing their job, no need for an LED projection on the floor to see if they were running, like nowadays!
