ok heres the deal i have a 99 Trans am. somtimes when i shift into gears it will grind. then while drivin in 4th if i pull out of gear then put pack into 4th it grinds. shifting fast into a gear with the clutch fully caomprssed it grinds.it grinds going ito 3rd also but in any gear when it grings it still goes into gear ans the clutch still holds. i just replaced the master cylinder. it's an ls6 clutch. any ideas

thanks,
Brad

 

sounds like you could have two things, bent 3-4 shift fork which is a common problem with the M6, and bad synchros which might have been caused my the bent shift fork.

 

i have the same problem any fast shifting in 2-3-4 it will grind...it's bad synchros most likely

 

Brad PM TwoFast4Lv, he's the nw's local tranny guru he did my trans as well as a bunch of other LS1 guys in the area.