This may help fix the problem.
Tremec has identified a range of TKO serial numbers that had bad shift lugs. If you contact them they will send you replacement parts and as I understand instructions for installation.
This post from Modular Fords covers the details of the situation and who to contact at Tremec. Click here =>
http://www.modularfords.com/forums/s...t=TKO+shifting
That being said TKO's as others have pointed out do not like to be shifted quickly above 6000. A smaller diameter disc(s) will go a long way towards improving the shifting experience.
Hope this helps.
Ed