I have a Whirlpool Duet Steam dryer purchased new in January 2013. (Can't find the model # in the dark.)
We have had an intermittent but annoying problem with clothes smelling like mildew. We were blaming being left in the washer etc. but I just opened up the dryer to check on a half dry load and the smell is quite strong-- I think it's coming from the dryer! The vent is just about 8' to the outdoors and I replaced it and keep it clean, I clean the lint trap every load and when I do some of our fluffy bath towels, I check in the middle.
It's not happening on the steam refresh I sometimes use, it's regular clothes/towels under "normal" drying conditions.
Any suggestions what I should check/what I could do? I leave the door cracked open a lot.