Hello my name isXXXXX will assist you
It is very odd to get a valve that does not close allowing gas all the time.
A more likely reason is airflow.
I would check the vent
Do you have any idea how long the vent is?
Sometimes, if you remove the vent from the rear of the dryer, can you see any lint build up
Do you smell the gas everytime?
have you done anything to the unit ? There is a pipe inside the dryer if that were to come apart you would have a issue like this.
I would recommend removing the top and the front panel, and then cleaning everything you see. you will see lint they all have it. Then you will have accesss to the pipe I am talking about
You are very welcome, please rate my answers before you leave. There is alot to be said for the plain jane huh?