They were working just fine all day today until tonight coming home in a bad rainstorm. When they are all the way down, they make this LOOOUD grinding sound for about 5 seconds and then nothing. It also happens when I lock the doors. Whats going on? They still opperate just fine but I definately hope the motor isn't going out...

 

your gears are stripped/stripping. You can replace the motors or brake them open and replace the gear. Brent Franker makes some nice brass ones(stock is plastic).

 

what he said, and replacing with brass gears you never have to worry about it again, and it costs less to do both sides than it does to replace one motor.