Loud and Annoying Door Actuator

The driver side on my '98 Montero makes noise everytime I unlock the door. It's kind of a grinding noise but it still unlocks and has for quite some time now. Short of being annoying it hasn't been too much of a problem. Does anyone know how to make the noise stop, or how to fix this before it DOES become a problem.

i think its the belt for the locks check that out

ours progressed so bad that when you try to unlock it, it keeps making a grinding sound, but will not exhibit the same problem when you lock it.

the dealer took a look at it and replaced the gear as it turns out, it was "stripped bare" already with respect to the unlock motion, so instead of stopping, it kept trying to unlock the door, leading to that grinding sound.