5th Gear Craziness

[Rokn Red]

Just got my 99 SS M6. Took it on open road to test everything and tried to get thru all the shift gates (at this point 5th). When I try shifting into 5th the shifter starts acting like it possessed (shaking erratically), grinds (clutch in) and won't go in (at about 70mph and 4500 rpms). All other gears work fine without any issues. Car has 84K, just received it via shipper from a South Florida dealer, so don't have much history other than what Carfax.

Any ideas and or solutions?

[30thbird]

Sounds like the problem is that you did not drive the car before you bought it. 5th is FUBARed and the box will have to come out/ be repaired.