Introduction; Rear Axle And Overrunning Clutch Operation - Toro Reelmaster 5500-D Service Manual

Introduction

Rear Axle and Overrunning Clutch Operation

The following explanation is intended to clarify the op-
eration of the 4WD rear axle and overrunning clutch
used with this TORO product.
A drive shaft connected to the front axle provides power
to the rear 4WD axle. The drive shaft incorporates an
overrunning clutch that transfers power in the forward
direction only (Fig. 1).
Front and rear axle gear ratios and tire sizes were care-
fully selected so during normal operation, the rear axle
input shaft turns slightly faster than the rear axle drive
shaft.
Note: The Four-Matic overrunning clutch may not op-
erate properly if different size tires are used, or if correct
tire pressure is not maintained.
Any time the front wheels begin to slip (climbing a steep
hill), the forward movement of the traction unit slows. In
this condition the rear axle input shaft speed also slows.
As soon as the rear axle input shaft turns at the same
speed as the drive shaft, the clutch will engage and pow-
er is transferred to the rear axle (Fig. 2). The result is au-
tomatic four wheel drive.
When the traction unit is turning, the rear wheels swing
at a larger arc and must travel faster than the front
wheels (Fig. 3). In this condition, the rear axle input shaft
is turning faster than the rear axle drive shaft and the
clutch in disengaged (overrunning).
4WD Rear Axle (Rev. C)
1
1. Four-Matic overrunning clutch
50 RPM
49 RPM
Unlocked
Rear axle
drive shaft
Page 9 - 2
Figure 1
Locked
49 RPM
49 RPM
Rear axle
pinion shaft
Figure 2
Figure 3
Reelmaster 5500-D