The gearbox as far as I can see is a very robust part of the bus.
The last time the bus was driven, the gearbox performed absolutely fine, the gearchange was smooth though there was a bit of excess play in the gearchange mechanism.

With the engine and drive shafts already removed, the gearbox is very simple to remove.

Dead easy, we put the jack underneath it (again using a piece of wood to prevent damage), Then undid the gear change linkage, this needs to be moved forward so that the gearchange linkage rear coupling is NOT attached to the gearchange input shaft. In fact slide the gearchange shaft as far forward as possible so that you can get your hand between it and the input shaft.
Now disconnect the earth strap that goes between a nut on the gearbox casing and the swing arm mounting bolt.
Next slacken off the clutch cable adjuster nut and remove the cable from the clutch operating lever (I actually removed the cable completely to get it out of the way).

There are now only four bolts holding the gearbox in, two at the front and two at the back.
Make sure that the gearbox is supported by the jack and carefully remove the two upper bolts from the bell housing side, these bolts go into anchor nuts attached to the upper gearbox mount which is in turn attached to the upper engine mounting frame.
Now remove the two front mount bolts from the bottom of the rear suspension cross tube and remove the cap piece.
With a bit of a jiggle the gearbox should be free, be carefull to support it correctly as it tends to be a bit top heavy.

As far as servicing is concerned, the gearbox internals should most definately be left to the professionals as the amount of special tools required are phenomenal.

Here is a list of the things I did to the gearbox

• Replaced thrust bearing.
• Serviced clutch operating lever.
• Replaced gearbox output shaft flange oil seals.
• Replaced gearchange input shaft seal.
• Fitted reverse light switch.
• Replaced input shaft oil seal.
• Cleaned and painted the whole thing.