Product review (5 stars): How to fix the smelly washing machine for good (replace hose and buy a Fan for the vent - permanent fix )
For the smelly washing machine:  The hose is great quality btw  - replace the hose first and then you will need to buy a 115 VAC 120mmX120MMX25MM fan (eg AC Infinity AXIAL 1225, Cooling Fan, Low Speed) and buy an 120mmX92mmX80MM fan mounting adapter kit.  (eg. Akust Aluminum 80mm & 92mm to 120mm Case Fan Adapter Blue). both are available on Amazon. to add the fan:  Remove the top washing machine  cover (3 bolts on back and slide it fwd and lift off). Mount the smaller 80mm side of the adapter around the vent on back so it enclosed it.  There will be a small gap on one side and you can add a piece of rubber 3/4" weather stripping ($4 dollars at lowes/Home D). After you add your weather stripping, line the holes up so you can catch metal on the washing machine.  pre drill the back of the washing machine (using slighter smaller holes thatn you mounting screws) by drilling through the 4 holes on the adapter.  Use some zinc hex screws and screw it in. Now mount the 120mm fan to the other end of the adapter.  It is a vent so you mount the motor so it exhausts and creates airflow out of the wash machine.  check arrow on fan for flow direction. (or plug it in before mounting to confirm flow direction).  Note - removal of the cover is so you can see where you are drilling so you do not drill into something you shouldn't.  This is the low speed fan that uses 8watts and they have a higher speed one with twice the CFM that use 18W and is an overkill in my opinion (too much energy usage).  Plug it into the wall and leave it on for years (do not unplug) you are leaving it on to dry out the passages to prevent mold from reoccurring. (so you want it to run 24/7).  The "Washer Fan" company has a patented magnet mount version that will be available in late 2016 for a $100 if you are not mechanically inclined and want to wait....  Additionally, some folks say washing with Borax with Tri Sodium Phosphate (TSP) in the HE front loaders will fix problem given the Phosphate's reaction properties with iron, sulfur,  etc