13. The selector shaft return spring should be tight on the pin pressed into the housing of the shaft. If not, replace the spring. The two snap rings and small lock ring on the shaft should be in good condition and seated properly.

NOTE: There is a right way and a wrong way to install a snap ring. This is true not just on the selector shaft, but for any part of any piece of machinery that utilizes snap rings, both internal and external. A snap ring is manufactured by stamping it out of an appropriately thick piece of steel. Because it is stamped, one side of the ring will have a sharp edge and the other side will have a slightly rounded edge. If you rub your thumb or forefinger across both edges of the snap ring, you will feel the difference in these edges (Fig. 48A). Snap rings fit into grooves which are machined with square corners inside them. When a snap ring is in its groove, it is usually capable of withstanding a greater side load in one direction without breaking or popping out, than it is in the other direction. This is because when the snap ring has its rounded edge forced against the side of the groove, the roundness tends to open it up, which can then allow it to be pushed out of the groove. On the other hand, when the ring is pushed in the other direction, it seats its square edge against the square edge of the groove, and is less likely to be dislodged. For this reason, a snap ring