I got my new DD clutch in and it went in easy and worked good for about the first 300 miles. The clutch still feels fine and works smooth but at about mile 300 of a 500 mile trip I cant hardly get it into 3rd and 4th, it feels like the synchros are going out. 6th is alos making a horrible slow knocking sound that got louder and I can feel it in the shifter now. I changed the fluid hoping that would help, and yes I overfilled it by 2qts like I always do but that didnt help at all. What could I have done to couse this? The transmission was shifting and felt fine before the clutch and for the first few hundred miles after it. Now it seems to just be getting worse. I dont think it could be the clutch because it feels fine and works smooth, I dont know if it is something I did during the install, its not my first install so I knew what I was doing, but I think it is wierd for these problems to come up so suddenly after the install. I was also running stock tuning and driving easy letting the clutch break in good, so I dont think I hurt the transmission by hammering on it.