15. You have now determined how many shims are needed to obtain the proper end play of the gearbox components. The final step is to determine on which end of the shafts these shims are best installed. Actually, the shims used in the five speed gearbox are so thin that it usually does not make much difference if the shaft is shimmed too far to one side or the other; but, in the interest of obtaining the best possible gear engagement and smoothest shifting, we will explain how to arrive at the ideal conditions.
16. Install the shifting forks on the shift fork shaft in their proper order as shown in Fig. 55A. Install two new snap rings on the shaft, being sure the sharp corners of the rings are facing inward, as explained in Paragraph 13, Section 3, of this Chapter.
17. The mainshaft, although having end play when you measured it, does not have any when installed in the engine. When the clutch assembly is put on the left end of the shaft and the clutch nut drawn tight, it pulls the shaft to the left until the mainshaft first gear is tight against the inner race of the ball bearing. What was previously end play is now merely a clearance which allows oil to reach the mainshaft needle bearings. However, when checking the transmission for gear engagement, the left engine case and clutch assembly are not installed. Therefore, a spacer must be made to simulate that clearance and hold the mainshaft in the proper operating position.