Kenny -
Check and see if the machine itself smells inside. I agree with Westie2 that there may be gunk build-up on the outer tub. If your wife uses a lot of cold or cool washing this time of year, and especially liquid softener, there could be 'slime' building up on the sides of the outer tub. I've been told that liquid detergent can add to this as well. I think we at least partially have non-phosphate formulations to thank for this.
If you want to dissassemble the machine a bit, you can verify that. Once not long ago I had to use half a roll of paper towel to wipe the literal POUND of slime off the sides of the outer tub of a large cap Kenmore BD which had been used with cold water, inexpensive liquid detergent, and softener. The slime was musty sour smelling, it was nearly black, and had the consistency of mayonaise. GROSS.
Several fills with hot water and bleach got rid of what I didn't wipe off, but the black water was unspeakable while it agitated. I had been telling the owners not to wash in tap cold water in the winter...they wouldn't listen...now it's warm or hot all the time for them as the dirty bleach water convinced them.
If you don't want to take the machine apart, try TIDE Washing Machine cleaner - I hear it's pretty potent and effective.
Gordon