General Information; Front Axle; Wheel Drive Rear Axle - Toro Groundsmaster 3280-D Service Manual

General Information

Front Axle

The Groundsmaster 3280−D and 3320 use a Dana
Axle, model GT-20. The differential and axle form the fi-
nal drive of the power train (Fig. 1).
The differential has a heavy duty case with automotive
type, cut gears that rotate on tapered roller bearings.
Single-row, pre-set, tapered roller bearings are used on
the outside ends of the axle shafts.
The entire drive line of the axle assembly is made of
alloy steel. The axle has a die-cast aluminum housing
that also serves as the hydraulic oil reservoir.
Power is transmitted from the hydrostatic transmission
output gear to the axle pinion spur gear. The pinion spur
gear transmits power directly to the differential drive
gears, to turn the axles and the front wheels.
The differential axle has a one-piece axle shaft with the
flange being part of the axle stem.

4 Wheel Drive Rear Axle

The 4WD rear axle used on the Groundsmaster 3280−D
is a steerable, mechanical drive axle. A drive shaft con-
nected to the front axle output shaft provides power to
the 4WD rear axle. The drive shaft incorporates a bi-
directional clutch that transfers power from the drive
shaft to the 4WD rear axle input shaft (Fig. 2).
Any time the front wheels change speed (e.g. initially de-
pressing the traction pedal, climbing an incline, tires
slipping), the rear axle drive shaft speed also changes.
As soon as the drive shaft and the rear axle input shaft
turn at slightly different speeds, the bidirectional clutch
will engage and power is transferred to the rear axle
(Fig. 3). The result is automatic four wheel drive. The
clutch engages in either forward or reverse direction.
NOTE: The bidirectional clutch may not operate prop-
erly if different size tires are used or if correct tire pres-
sure is not maintained.
Groundsmaster 3280−D/3320
FORWARD CLUTCH
ENGAGEMENT
Page 8 − 3
Figure 1
Figure 2
REVERSE CLUTCH
NEUTRAL
(FREEWHEELING) ENGAGEMENT
Figure 3
Drive Axles