yeh mate it is a rattle sound, as soon as you put the clutch in it quite, lift your foot of the clutch and then the rattle back so it the thrust bearing but if it only done 10k it should be fine, the car done 57k now, has it always made this rattle sound since you do the SMF conversion ??? to me it just sounds like the thrust bearing dry and need replacing or a very small amount of grease on it