The washing tub is basically two parts. One the inner tub made of stainless steel and is the moving part. Then the outer tub made of plastic which retains the water. On front loaders the outer tub is of coarse on its side and tilted slightly toward the back. At the bottom of the tub is the connection for the drain. See part #22 in diagram Parts for Frigidaire FAFW4011LW0: Motor / Tub Parts - AppliancePartsPros.com

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At the bottom of the plastic tub you will see the rubber drain hose leading to the drain pump. There is water still in it most times so if you can drain it out before removing with a wet vac do so. Remove that rubber hose from both the tub and drain pump. Clean thoroughly the rubber hose and the pump. Also if you are able to vac out any residue in the bottom of the plastic tub thru the opening where the drain line was. The sludge build up is usually toward the back of the tub. I get creative and tape a small rubber hose to the end of my wet vac hose to get up in there. Also check to see if any sludge build up is in the pump itself.