Hi, I recently had a repairman check my washing machine due to mouldy smell. After running a water test (which tested fine) and checking the water filter and detergent drawer, he concluded that the smell must be due to bacteria growth on the drum (he didn't check it, just assumed). He said that replacing it would be around $500. Does this sound reasonable? Also, do I need to replace the drum due to bacteria? Is it not possible to just get the drum thoroughly cleaned? BTW, it is a kenmore front load machine, model number 417.44142400. . thank you!