Driving along today, came down a short incline and needed to brake. After braking all of a sudden a knocking noise from what seems to be the transmission tunnel. I drove along slowly for a bit and under power the noise went away, but when I pulled up again, the knocking noise returned. Clutch fully depressed, the noise stayed constant, engine at idle. Engine runs fine. No rough idle Seemed to happen after braking Clutch has been operating just fine with no slip Gears working fine, changing smoothly, no noises. Got home and let it sit. Went and had dinner, sat down and got my head straight, went back out and and started the car. Knocking disappeared Drove it round the block, did some braking, still no knock. Drove home and car quiet and well behaved. What is going on? Flywheel? Clutch? Brakes? Driveshaft? (By the way where is the driveshaft(s) on a front drive?) I thought something to do with brakes maybe, because it happened right after braking, though the knock seems to be in the transmission. Now it's gone, but I'm obviously concerned there is something ready to go if I don't work it out. I've got it booked into the garage but I'll bet I won't be able to reproduce it for them.