Timer, occasionally not shut-off and was getting very hard to start the dry cycle.

Removed three torx-head screws from the top of the control cover, moved the control cover towards the dryer door and up, released the four-tab cover from the timer knob (the four tabs can easily be seen and released if your standing behind the dryer), removed timer knob and selector ring, removed wire harness from timer, slid timer out of locking tabs. Reverse procedure to install. I would recommend buying the four-tab knob cover as well as the timer. The tabs could very easily be broken and the timer knob will not stay in place or function properly w/o the four-tab cover.