that noise might be the tranny.mine does the same thing.its not really a big deal,i mean its not like the tranny is goin to fall out.i have a friend with a 91 dx hatch and its a 4 speed and makes the same damn noise.try and push the clutch as the car is parked and see if the noise goes away.if it does its jus like mine.i got a hf and for everybodys info hf's have a rear wiper and they are 16v per cylinder.the 90-91 have the dpfi.what year is the crx.i think if it has ac than its a dx.