vibration at high speed

[TXGTP]

04 cobra 49k miles on the highway when im going about 60 and i drop into 4th and bring it up over 100mph i get a nasty vibration noise that i can hear and feel thru the shifter...its also hard to put into gear after this...any ideas
?..ive got a fiore clutch quadrant and firewall adjuster sitting waiting to be installed..thanks..

 

[R1Psycho]

I get the same vibration/noise in the top of 3rd and 4th, but mine isn't hard to get into gear. If I ever figure out what the deal is, i'll let you know.

 

[dsgsnake03]

i have the same problem. im thinking its the tob

 

[TXGTP]

makes sense