Here's the problem: When I'm driving normally, I hear a little grind everytime I upshift accelerating. But worse is slowing down; I must brake engaged in gear before I can dissengage the clutch and put the trans in neutral when slowing down or coming to a stop. If I dissengage the clutch and put the car in neutral at speed, using the brakes to brake and not the engine, I get a loud noise that sounds more like a metal friction noise than a typical gear "grind". One mechanic told me the synchros were going bad, but I've read that that's rarely the case. It has recently got a new clutch, which two mechanics inspected and is fine.

Any ideas? The car has just under 100,000 miles.