overtime the gearbox will grind on itself more, try dropping the fluid make sure theres no metal bits coming out, maybe u are just low on fluid. i remembered help changing one of the forum members gear box oil here. he had the original factory oil for 130k and it was basically almost like "black water" had just under 1 litre inside. after replacing it with the castrol syntrax 75W90 and 125ml of Nulon Gearbox additive, shifting has very much improved and the crunching dissapeared. FYI - our stivo boxes take 2.3L of gearbox oil, so u'll need 3L of gearbox oil. the additive is optional