Jock,
While you are setting up the end float clearance, check that G6 engages deep enough with G11 when 4th gear is engaged as Bill Thomas mentions. I check this by placing a piece of bluetack on the appropriate part of G11 (the large double gear) where 4th gear G6 engages. Put the box together and select 4th gear. Then dismantle and check the two gears are engaging deep enough by looking at the impression in the bluetack. If 4th gear doen't engage deep enough, it can jump out and round off the teeth. This can then over time put side load onto the selector arm that engages G11 and eventually wear the selector. Then a new selector, G11 and G6 are required (don't ask how I found out!!!).
When I put my gearbox together correctly checking everything, I put two shims in totaling 41 thou thick and this still gave just over 5 thou clearance on the mainshaft. The total thickness of the shim is not important. Good engagement of 4th gear is, along with 5 to 10 thou mainshaft end clearance as Trev states.
Cheers,
Simon.
While you are setting up the end float clearance, check that G6 engages deep enough with G11 when 4th gear is engaged as Bill Thomas mentions. I check this by placing a piece of bluetack on the appropriate part of G11 (the large double gear) where 4th gear G6 engages. Put the box together and select 4th gear. Then dismantle and check the two gears are engaging deep enough by looking at the impression in the bluetack. If 4th gear doen't engage deep enough, it can jump out and round off the teeth. This can then over time put side load onto the selector arm that engages G11 and eventually wear the selector. Then a new selector, G11 and G6 are required (don't ask how I found out!!!).
When I put my gearbox together correctly checking everything, I put two shims in totaling 41 thou thick and this still gave just over 5 thou clearance on the mainshaft. The total thickness of the shim is not important. Good engagement of 4th gear is, along with 5 to 10 thou mainshaft end clearance as Trev states.
Cheers,
Simon.