My car is a 90 535 5 spd with 133k miles. Lately, when shifting into 3rd from second and sometimes during a downshift, it grinds. Now, this does not occur at lower RPM's, but above 4K, it happens about 75% of the time.. Clutch seems Ok, doesn't happen in the other gears. I'm running Redline in the gear box, diff and clutch. Could it be a syncho? Trannny problem? Is it time for a clutch and flywheel change??![]()