Service Manual

5-4

WPM Drive Systems Manual

THREESPEEDTRANSMISSION

The shift keys are retained on one end by the shift

collar. Movement of the shift fork positions the shift collar

and shift key. The shift fork is supported, both top and

bottom, by nylon bushings for smooth operation and long

wear (Fig. 117).

The operator controls movement of the shift fork by

means of the gear selection control and cable.

Note: Therearenoshiftdetentsinoronthe

transmissionon1988andnewermowers.

There are also three gears on the output shaft. These

three gears rotate freely on the gear sleeve. The gear

sleeve is coupled to the output shaft with a roll pin so

the gear sleeve always rotates with the output shaft. The

gear selection system determines which one of these

three gears will be coupled with the gear sleeve and the

output shaft. This determines the nal drive ratio.

Gear Selection System:

Gear selection is determined by moving sliding shift

keys in a sleeve that is xed to the output shaft. These

keys engage one of the three gears that rotate on the

gear sleeve. Once the key engages one of the gears,

that gear will rotate the output shaft. Table 1 shows

approximate speeds in gears for two different engine

speeds.

Table 1

Gear Ground Speed @

3000 RPM

Ground Speed @

2000 RPM

1 1.8 mph (2.9km/h) 1.2 mph (1.9km/h)

2 2.7 mph (4.4km/h) 1.8 mph (2.9km/h)

3 3.8 mph (6.1km/h) 2.5 mph (4.3km/h)

Fig117 3428-0065

A. Gear Sleeve C. Keys

B. Shift Collar