Hello this is my first time posting here as I had encountered the same problem with mixed results, finally ascertaining this was a mechanical issue pertaining to motor armature/encoder flag wheel out of position in relation to the motor rpm sensor hose shoe through normal wear of the forward bearing wave washer and motor housing alignment. The housing screws need to be tightened firmly as possible ensuring proper flag sensor alignment and also replace or reform wave washer (the main culprit) ensuring positive armature down force towards rear of motor housing ensuring proper encoder flag photo transistor sensor position. when reinstalling motor be sure motor mounts in frame completely seated clip should go on relatively easy reassemble dryer and have cold one like I did not spending any money on this ensures a wife friendly beer purchase and clean DRY clothes enjoy this simple repair. I also tried the transistor only to realize thruogh voltages checks and electrical component tests that the encoder circuit was indeed functioning properly leading me to this simple wear and tear easy fix, let me know if this solution helps any of you. The armature wave washer belongs in the front bearing race. (front of dryer facing)
And The TRUTH Shall Dry You Free (pun intended).
Thank you all for helping to lead me to find the solution to this problem.