Took it apart this evening. That part of the operation takes about an hour, as the whole top and side of the printer basically comes off to get at the scanner assembly. The encouraging thing, however, is that when I got to my goal, the description of the Laserjet motors that I mentioned in the previous post turned out to fit the LW8500 like a glove: e.g., http://www.fixyourownprinter.com/forums/laser/42093 .

I can feel a little roughness in turning the mechanism with my fingers, which would presumably be A BAD THING at very high rpms, more or less like an ageing water pump in a car that feels just a little rough to the hand nevertheless makes its presence known by grinding loudly when you drive down the road.

In the scanner motor, there is a ball bearing assembly around the driveshaft that I will lubricate. The good thing is that nothing is yet stiff, so no real damage has yet been done — the printer has, after all, been lightly used. But I will need to get some better machine oil than I presently have to use on it, before reassembly and testing. Will post the results in the next day or two.

It will be interesting to see not only if it works, but whether the scanner motor whines less on reassembly.

Fingers crossed!