I'm guessin with 97K you've replaced the clutch at least once, but anyway, i hav a 94 that did the same thing after replacing the tranny, and double check how well the bellhousing is matched up to the engine block. also check for any leaks that might be causing minor slippage. the noise on mine went away and i haven't had any trouble with it, it engages fine and doesn't slip at all, so maybe something is just workin itself in. hopefully it ain't a pilot bearing, that's a pain in the @$$. check those deals and see what you can find.