[Spridgets] Rib case gearbox

[roger cotting]

 I rebuilt a ribcase gearbox: new laygear,shaft, and bearings; new 1st motion
bearing; new mainshaft bearing; new  rear oil seal;Three syncro rings . All
shift forks were checked for proper width. The mainshaft gears were checked.
The gearbox jumps out of third gear. Any thoughts? I used the Moss replacement
for the rear bearing and shimmed it acording to the instructions.
Roger
Cotting