Just bought a 2000 Buick Park Ave, clean, 175k miles. Engine runs well, tranny a bit clunky shifting under acceleration. Driver's power seat works fore and aft and the seat back tilts okay, but the vertical up/down for the front and the rear of the seat (seperate motor/gear drives for each)don't work. The motors run, but the gear boxes don't engage the threaded rods they should actuate. I have the seat out and upside down on my garage floor, it doesn't appear that any of the parts were particularly made to be replaced. Anyone have any success trying to rebuild the gear drives or am I looking at a whole new seat rail? Local salvage yards have been a bust, have a few more to check,anyone have a good source for a seat rail? I need to get this fixed fast as it's stuck in the up position, placing my cranium up in the headliner and the rear-view mirrow directly in my line-of-sight, obscuring such items as my Massey 202 and AC B.