93 4 Runner Headlight Adjustment

Jay
I'm having no luck adjusting the headlights on my 93 4 Runner. I turn the adjusting screws but doing so has no effect on the tilt or angle of the headlight. The adjusting screws go into white plastic housings. Does anyone know if those housings are gear boxes? If they are, they probably contain some striped gears and need to be replaced. I sprayed some WD40 on the screws - maybe that will loosen thing up.

Thanks,
Jay