Product review (5 stars): I easily replaced both valves (couple of screws and 2 wire ...
My Whirlpool gas dryer was working sporadically, meaning the flame would initially come on but would not stay on. I tested the resistance of the the two valves using an ohmmeter. One valve tested was not reading what the manufacturers manual said it should.  Bought the set of Whirlpool gas valves on Amazon. I easily replaced both valves (couple of screws and 2 wire connectors), and now the dryer works perfectly. These on/off valves control the gas entering the chamber, where a flame is created to heat the dryer drum. Buy and replace both, because the two valves work together.