Hi, i'm having an issue with my 93 tt 5speed. When ever I drive on the freeway for 30 mins or longer with minimal shifting (like cruising in 5th gear for 30 mins) it will grind when i down shift to 4th gear. I does not grind on any other gear. It almost feels like i did not press the clutch in all the way but I know I did. The 4th gear grind goes away after I park the car for an hour or so. Then it will be fine when I drive around town with no grinding on any gears.I can only replicate the problem after a prolonged freeway drive with minimal shifting. Any ideas? thank you in advance...