I have a Frigidaire front load washer that is working fine, but makes a loud vibrating noise when draining.

First question. Is the drain pump supposed to run the entire time during the spin cycle. Mine does even after the water is drained.

From reading the forum, I see that this problem is usually caused by a blocked filter, something stuck in the pump or a bad pump.

I took the pump out and inspected it and did not see anything in it. I connected it to 110v and let it run while sitting on the floor and it was very quiet. I removed the rubber boot that feeds into the pump. It had some lint caught in it but not enough to obstruct the flow.

I cleaned out the boot thoroughly and re-assembled everything. After putting it back together the noise is still there.

The only strange thing I noticed is that the check valve on the pump looked like it was too big for the opening. Since it was not damaged in any way, I assumed it was correct.

I am hesitant to replace the pump because it runs so quietly outside of the washer. Is there something I forgot to check?

Is there some way I can make the drain pump run with the front door panel removed?

Thanks
mike