Bicycle Tutor

I ride a 2006 Stumpjumper Hard Tail. I have two sets of wheels for this bike -- the stock OEM 26" wheels for mountain biking, and a set of Mavic Speedcity 700C wheels for the street.

The hub on the rear Mavic Speedcity recently began squeaking. It's definitely not the disc rubbing -- I can remove the wheel and slowly turn the (XT) cassette by hand and hear the squeak. It sounds vaguely like "rubber on metal", so I suspect one of the rear seals has failed.

Given that tiny bit of (probably incomplete) information, how likely is it that a rear hub seal has failed?
If it is a seal, could this result in other damage (in other words, is it a simple matter of replacing the seal, or must other components be disassembled/inspected for problems)?

If it's not a seal, what else could cause such a squeak when the cassette is rotated?

Thanks!
KM

Tough to say given just this info. But squeeks in general are not a good sign. It's not that hard to take out the axle and freehub. Might be worth it just to see what's going on and relube everything.