type 9 sierra

[max]

hi anyone know a gearbox specialist sometimes notice mine jumps out of 3rd and 5th gear would like to get it repaired  in the winter 

[fry61]

Take all the gear shift covers off first & check for good all round clearance in all gears & differing throttle use.  A lot of problems ( mine included ) were down to just a slight touch between shift & scenery 

[max]

Thanks will check

[brumster]

From what you say, sounds like it might just be a worn aspect of the selector mechanism, a lot of which is accessibly pretty easily through the top 'hatch' and is pretty easy to replace if need be as it's one of the first things you disassemble out of the gearbox if rebuilding it.

[MarkBzero]

Check the selector saddle, it could be broken or worn.

[max]

will remove gearbox in the winter and check thanks guy's 

[Kerry]

If its a late type 9 box there is a plate on the side of the gearbox extension housing, it has two bolts through elongated holes that can be loosened, and the plate can be moved forward and backward to give a better gear selection. I have just rebuilt Dean Rudkins gearbox and adjusting this plate make a big difference and will probably compensate for possible wear in your selectors.