First I would disconnect the linkage at the ZF
and shift, that will tell you if it's in the linkage rail.If that's OK it could be in the ZF at the cross shaft, if it's stiff in all gears you could have a broken spring that will make a spacer on the cross shaft preload at 45 deg. witch will make the cross shaft hard to rotate.That is where I would start.If the shift rail is stiff when disconnected you may have to remove the detent in the shifter box in the car and work your way back to see the problem.
[This message has been edited by Lloyd Butfoy (edited 04-03-2001).]