I have a 2018 Model S. A couple of weeks back I experienced the same issue described in the first post - The driver side door handle would no longer present but I could hear the motor spinning. Fortunately I could still open the door from the outside by pressing in the door handle, which unlocked the car, and then opened the door by wedging my fingers behind the driver side window.
I used to own a 2016 Model S on which 3 of the 4 doors experienced the door handles not presenting issue. I fixed them using the microswitches & paddle gear kit from EV Tuning. I was expecting the same problem but saw that the 2018 has Gen 3 door hardware. Taking the Gen3 door handle assembly apart, I noticed that the problem was caused by a broken door handle motor gear, not the paddle gear.
I scanned the web but couldn't find any place that sells a replacement for the handle motor gear. I next looked for used door handle motors without much success. Thanks to the suggestion from
@T100d- I decided to order the recommended part from Amazon. It arrived in a couple of days and as noted, the bore size is smaller (5mm) than required (6mm). The length of the gear is also smaller than the original Tesla part. However the new gear seemed wide enough to engage with the paddle gear.
I used a drill to increase the bore size to 15/64". It was a tight fit as I needed to use a hammer to gently tap the new bored gear on to the motor gear shaft. Since the motor shaft is 'D' shaped and the bored out gear was round, I put a drop of Loctite Super Glue Ultra Gel Control on the shaft once the new gear was in place. I put the motor upright on a table for the night to let the Super Glue seep into the gap between the gear and the shaft.
The next day I put the motor back into the door handle assembly and installed it back into the car. The door handle started working again without need for calibration! It's been only a couple of days since the replacement but so far the new gear seems to be holding well.
I have attached a few pictures that show the original gear next to the new replacement gear. The last picture shows the new gear installed on the window motor.