I was at the drag track a few weeks and I dont know if this has anything to do with anything but this is when I started haveing transmission issues..I missed 3rd gear or should I say that I went to go put it in 3rd and I didn't have the clutch pedel fully pushed in and pretty much rammed it in 3rd.i knew I messed up when I did that but nothing happened that day and the car drove smooth on my way back home.i had parked it for a couple of days after the whole track ordeal and then decided to drive it to work,every thing was smooth on my way to work (50miles going) but on my way back home and 30 miles in I was stoped at the red light, it turned green and I switched from 1st to 2nd then to 3rd and when I tried to switch to 4th I couldnt get it out of 3rd gear, it was STUCK so I pulled over turned the car off and i managed to get it out of 3rd gear easily while the car was turned off..for the rest of the drive back it kept getting stuck in 3rd gear but this time with some force I managed to get it out of 3rd.

Anyways got home and parked it for a few days then yesterday i decided to drive around the neghiborhood to see if it was still acting up and this time it wasn't getting stuck in 3rd gear but it is now grinding in 4th.It grinds only when I go put it in 4th gear..its like a grind/crunch feeling and sound..
I useally have to double clutch and wait to the rpms drop under 1500 rpms for it to go in smooth..when i go from 3rd to 4th it grinds but when I downshift from 5th to 4th there isnt any grinding. Its weird.once it is in 4th gear its all good and dosnt grind..I am able to switch in all the other gearz good..
Could this be related to the clutch?the shifter is stock and not aftermarket,I should also mention that the clutch pedal goes to the floor if im raceing it hard, its like theres no pressure.
The car is a 2002 z06 with H/C, headers,exaust,intake and is currently 440-465rwhp..im not done getting it tuned and haven't got it dynoed.
Thanks for any and all help/advice

 

be sure the shifter is aligned. hard shifting can knock it out. but it sounds damaged. best of luck

 

Okay, lemme see... It sounds like you might have bent the 3rd gear shift fork(hints it getting stuck in gear). Not sure about 4th gear but my first gear was the opposite, it would grind downshifting to 1st but would go in at a stop fine.
Clutch sticking to the floor is a common c5 problem, changing the fluid will help it 9 times out of 10. All in all you will eventually need a tick master cylinder and bleeder.

 

Bent fork.