Oh goodness NO! I didn't mean to imply that! The gearbox can come out as a whole unit, beling slipped out the left side of the machine. Now comes the tough part.... memory... it has been awhile.
As I recall, you must remove all of the belts. I think you also have to remove the transposing gearbox (where the metric change gears would go). Pulleys must be removed, as appropriate. Then there is also a plate below the front of the gearbox that must come off. This will expose some bolts; the remaining bolts can be easily viewed from the headstock end. Finally, I recall you must remove the speed pot, a few linkages and the lockout solenoid. I *know* the latter is required because I forgot that one! The result was that the gearbox functioned very well as a pair of scissors on the solenoid wires! Anyhow, that should be about it. After you've accomplished the above, the gearbox will slide out along the axis of the machine (i.e. not out the front). Oh, needless to say, the drive rod and leascrew must also be removed. I did this by removing the leascrew support on the tailstock end (all easier if you don't have electric leadscrew reverse).
I am probably not the best person to answer your questions because it has been awhile since I did all of this. There are plenty of people on this list, though, that probably remove gearboxes (Alex, Dave [concentrates on round dial types], Harvey) on a regular basis. At the very least, however, I can absolutely tell you that you need not remove the headstock.
Alan
[This message has been edited by wrench (edited 02-24-2003).]
[This message has been edited by wrench (edited 02-24-2003).]