It's probably one of two things:

1. The main pump/motor seal is broken. Normally, this would cause a larger leak than what you are describing, but if the seal is just starting to go, it would probably not let too much water out. Click on the diagrams for Model HDA105Y-70WH. The seal I'm referring to is number 434 on the pump/motor diagram. There are two ways to fix this problem - rebuild the pump using a pump seal and impeller kit (more time and effort, less money) or replace the entire pump/motor assembly (more expensive, but a much quicker and easier repair). Instructions are included with both kits.

2. Small rubber seal for the pump drain valve shaft (located right above the solenoid, number 417 on the same diagram) is worn out. This will produce a minor water leak, much like what you are desciribing. The new seal also comes with instructions.

It's pretty easy to tell whether the problem is with the pump seal or the drain valve shaft seal. If the water is leaking from the bottom center of the motor, the pump seal is bad. If the water is leaking from the drain valve shaft (right above the drain solenoid), the shaft seal is bad.

Hope this helps. Let us know what you find.