Noises are extremely difficult to diagnose, particularly from off site. I would do a tear down process in this order, and just keep working until you find the problem. Before that I would take off the cabinet, bypass the lid switch and operate the machine briefly in spin mode to see if you can hear exactly where it is coming from. Remember, in doing this you have disabled a safety device so be very careful and do this for a very limited time.

If you cannot isolate it then you could

1. Remove the agitator and inspect top of drive tube.

2. Remove cabinet, pump. Mannually turn motor clockwise and listen.

3. Remove motor and plate to get to the transmission. Remove transmission and inspect. Turn it in spin direction and listen.

4. Remove drive tube and inspect.

It has to be there somewhere!