I see...that makes sense. So would a long run of say, 25-30 feet cause the back pressure?
The vent tube itself is good.
What is that material: smooth-walled, rigid aluminum duct sections or the slinky collapsible stuff?
I know because I have inspected it. And I feel what seems like good airflow at the terminus.
Unless you have a calibrated palm like us certifiable Appliantologists, then you can't really tell if the exhaust pressure is good or not because you don't have the experiential basis for comparison. In that case, you need to rely on an instrument, such as this pressure tester ==> http://www.repaircli...0106710/1447456
However, there are two 90 degree bends in the system... If I shorten the run length by more than half would you consider that a proper fix? There is not an easy way to get around the two elbows. The house is pier and beam foundation, and the dryer vent goes through the floor and out one of the vents in the crawl space.
I refer you to the Oracle: The Ultimate Dryer Venting Guide ==> http://fixitnow.com/...-venting-guide/