Improper use of ANY washing machine will can cause built-up of mold. There have been several threads about mold in top loaders as well.

The key is to use the machine correctly and, in your case, do not use that EcoBoost option on your Whirlpool too often. The reason why Affresh was supplied with your machine is because Whirlpool makes Affresh. Giving away samples is an easy way to sell your products. As for cleaning your washer: if you want to do this, I'd say use Smelly Washer. It seems to get better reviews that Affresh and will also work in your TL - despite the Clean Washer with Affresh cycle... ;-)

Alex

Thanks. Does having a water softener help reduce the formation of the odor or does it help in having an odor?

If you have soft water, you can use less detergent, as hard water "eats up" detergent - so to speak. On the downside, soft water rinses worse so you might need to use Extra Rinse for some items like towels or underwear.

I don't see any obvious connection between hard water and odor - provided the detergent is dosed properly. One benefit is certainly that nozzles and the screen in the water inlet hoses won't clog up with lime scale.

Alex

I keep seeing where people say use he powder detergent if you can as this will help minimize the build up of gunk, thus not requiring the affresh type stuff. Any truth to that. I am getting ready to use my washer for the first time and would like to start out on the right foot.

Liquid detergents often do not contain any type of bleach, which can help to clean the washer and keep bacteria growth to a minimum. I'd advise you to use some sort of bleach for your whites along with hot water (Bright Whites cycle). This can be a detergent like Tide with Bleach powder, Sears with Oxy etc. - or you can add a separate oxy powder to your wash load. Chlorine bleach works at all water temps - but it's harsher than oxy.

Alex