How do I access the drain pump on Kenmore Series 400 washer?

How do I access the pump on a Kenmore Series 400 triple action agitator washer? Model 110.23102311, type 587-20. Does the outer cabinet of the washer need to come off? What tools would be needed to do this?

Flakes of old dirt come into the tub and are visible when the cycle is done. Sometimes the water won’t drain properly and the clothes are still dripping wet when the cycle is complete. There is no noticeable smell.

I have tried using Affresh and the clean washer cycle with hot water to flush out the pump, several times. I just tried that again 7 times in a row, and also thoroughly scrubbed the entire inside of the tub as well as the agitator. I still end up with flakes of old dirt in the tub, usually near the bottom of the tub and sometimes a bit on the agitator. It is not rust. Occasionally rust will fall in from the top of the inside of the cabinet, but that looks much different than the dirt flakes I’m talking about. The washer is pretty new, but had been used roughly by others in the past, including someone who would often have rocks, nails and cement dust in his pockets after work. I think there must be debris affecting the pump and would like to check it.

Thank you