Jiles

I have a Trek X-Caliber 9 that has a slight grinding noise while pedaling and quiets up a little when coasting.
I took the wheel off and spinning the cassette produces a sound like a dry bearing.
Is there any periodic lubrication for a freewheel?

Andrew R Stewart 

Gee, usually a cartridge bearing at no spin is fairly quiet Maybe a few creaks as the bearing rocks a bit. But the same bearing spinning usually is rough/loud/whinny. Perhaps the ratchets are dry instead. You could take the freehub off the hub shell and drip oil through it and reinstall. Freehubs these days often use tiny balls, and not cartridge bearings, and get worn quickly if the lube washes out. Replacing the FHbody might be your final result. But without doing things myself who knows for sure. Andy

dabac

Any noise while pedalling shouldn't be from the freewheeling mechanism, on account of it not moving while pedalling. You need to look elsewhere.

Andrew R Stewart 

Not always true. We see low cost freehub bodies with rusty/washed out of lube internals that can crackle as the crank rotates. Depending on the cog the chain is on a slight sloppy rocking can also contribute to the noise. Then there's the classic Sun Tour freewheel knock only heard when pedaling. Andy.