996 MAINSHAFT TECH TIP

The 996 mainshaft has a keyed thrust washer between the 3rd and 6th idler gears. This washer is keyed to a slot on the mainshaft. The washer will rock in the slot until it damages the mainshaft and the shaft will then need to be repaired or replaced. In the worst case, the hardened washer will shatter and the pieces will run throught the gears. This is a very common problem and needs to be checked any time the gearstack is apart.

An undamaged mainshaft has crisp keying slot edges.

The flat on the washer will elongate the keying slot by rocking.

The flat on the washer will wear, leading to failure.