To replace a shift cable on an MC1 drive (no such thing as pre-alpha), remove the drive. Remove the inner part of the cable. Tie a draw cord to the engine end of the outer. Cut the outer near the bell housing and pull it out, pulling the draw cord with it. Remove the stub from the bell housing and run a straight tap down the threads to clean them up. Fit new shift cable bellows and using the draw cord, pull the new outer into place. Thread the new outer into the bell housing, push the new inner into the outer, fit the drive and set it up using the correct shift cable adjustment procedures.
For a better and more details procedure, read the appropriate sections of the service manual (genuine factory of course).
Chris...........