I have tried several things and been on another appliance forum, but still haven't isolated problem.
When load size is set to the highest level, As the machine begins the spin cycle, the tub is still completely full of water, the spin speed increases slowly and water starts overflowing through the overflow channel on the front side of the tub lid because the tub is still full, but centrifugal force causes spilling. As tub speed gets faster, tub starts draining and tub does completely drain and it successfully completes spin cycle, except for the water that spills onto floor.
The motor, drum, and pump are all connected to the same belt, so unless it has some way to disengage the drum from that belt, the drum and pump always spin anytime the belt spins. Pump doesn't seem to start draining tub until tub is spinning very fast.
I completely disassembled the pump and drain tubes. All were clear. Pump looks brand new inside. No damage, clogs, gunk, etc. I also thoroughly cleaned the tub basket and lid many months before this spin cycle spilling started.
I have checked and blown out the fill level tube twice. Always seemed clear. With water in tub, I disconnected from sensor end and blew out tube and heard bubbles. I also blew into tube from tub end and felt pressure in the sensor.
Wondering if it's filling the tub too much during the wash and rinse cycles, but I don't know how high the water should be for a full load.