Please take a look at the following link. In particular, the first major paragraph where it discusses proper ventilation:
I know the link is for a dryer that no longer heats, but if a dryer is left in a condition where it is starved for air, the heating circuits will actually over-heat and eventually fail. You need to ask yourself when was the last time you inspected or cleaned the dryer exhaust ventilation. If you can't remember, or if you've never cleaned anything before, it may be a good time to do so. Most dryer heat related problems are caused by poor ventilation and lack of cleaning. I recommend that you clean the dryer ducting twice a year. That's once in the spring, and once again in the fall. It is also important to note that the SHORTER and STRAIGHTER the exhaust vent line is, the BETTER. The more bends and kinks that you put in the dryer exhaust, the more resistance you create for the dyrer blower, and the more potential choke points you create where lint can accumulate and clog. Not to mention, this can also cause a fire hazard and/or a habitat for rodents.
Follow the recommended advice and try drying a load of clothes with the vent hose removed, first. If your clothes dry faster like they should, you may have an exhaust clog somewhere. If your clothes still aren't drying correctly, inspect the interior blower fan housing for obstructions. This is all explained in the link provided.
If you attempt these preliminary measures and still have problems, please let me know. I hope you find this information helpful.