Simon,
I'm going to hazard a guess you are talking about a 4 speed synchro box, though this still leaves at least two versions; and the input shaft has two bearings...
I'd suggest looking at Harold Perry's account on p149 of the A7 Companion, it should tell you all you need to know.
The 'secret' is that you must drop the layshaft cluster off its shaft before you can get the top gear sets out. The input shaft should then simply drift out from inside together with its main bearing, once the front cover (and with it the smaller roller bearing) has been removed. A warm box is much easier to strip than a stone cold one.
Sounds like a selector sleeve has sailed over its detent balls and released them - indicative of too much end float somewhere.
I'm going to hazard a guess you are talking about a 4 speed synchro box, though this still leaves at least two versions; and the input shaft has two bearings...
I'd suggest looking at Harold Perry's account on p149 of the A7 Companion, it should tell you all you need to know.
The 'secret' is that you must drop the layshaft cluster off its shaft before you can get the top gear sets out. The input shaft should then simply drift out from inside together with its main bearing, once the front cover (and with it the smaller roller bearing) has been removed. A warm box is much easier to strip than a stone cold one.
Sounds like a selector sleeve has sailed over its detent balls and released them - indicative of too much end float somewhere.