dryer 101.....dryers take three thing to dry......
heat. generally they heat or not, no in between
air flow....they need to be able to exhaust the heat and moisture to dry. if the air flow is hampered the drying times get very long and you get warm damp clothes.
I am very confident the vent from the back of the dryer to where ever it exits the house is compromised in some way, whether it is very long, a lot of 90 degree bends, up through the roof, or clogged with lint, water, a faulty vent cap outside, or even a critter nesting in the vent to escape winter. CURE TE HOUSE VENT PROBLEM AND YOU FIX YOUR DRYER THANKS AND HAVE A GREAT 2010