It's always best to start a new topic for your own appliance and if you feel a topic maybe related to yours reference it with a link.
I have done it for you this time.
So is the model number of your dryer also WED6400SW1
The first thing I always check on any electric dryer that runs, but does not heat is the voltage to the dryer. Do you have 220-240 volts at the dryer? If one leg is missing you could have only 110-120 Volts and this could let the dryer run and not heat too.