There are a couple reasons it may shut down. The motor may be overheating. You can check by turning on the dryer and wait for it to shut down, try immediately restarting the dryer. if it wont start then wait ten minutes and try again. if it starts then more than lijkely the motor is overheating. another is a moicture sensor telling the dryer there is too much moisture in the dryer. If it will run empty without shutting down, more than likely a bad moisture sensor. A bad belt which if the drum turns its not the belt. Try the lint filter and make sure it is clean. Good luck