Transmission Charge Pump - Toro Groundsmaster 300 Series Service Manual

Transmission Charge Pump (Fig. 20, 21)
1. Remove the drive coupling from between the engine
pulley and the transmission hub; refer to "Removing
Drive Coupling" in Chapter 10.
2. Remove the taper lock (if applicable) and the hub from
the transmission shaft.
3. Examine the transmission pump shaft and remove all
burrs, sharp edges and residue to prevent possible
damage to the lip seal.
NOTE: Disassembly of the charge pump is not neces-
sary when the seal is the only part that must be replaced
(see step four). Servicing any other part of the charge
pump requires disassembly (see step 5).
4. If the charge pump seal is the only part being ser-
viced, pull the seal out of the charge pump housing
using the oil seal puller or similar tool. Do not scratch
the pump shaft. Since oil flows out of the transmission
when the seal is removed, use a drain pan to catch the
Figure 20
oil; however, do not use this oil again.
5. If the charge pump must be disassembled, scribe a
mark on charge pump housing and adjacent pump
housing to assure correct installation when parts are
assembled.
NOTE: Charge pump housings that have the letters LH
and RH on the external surface must be installed with
the letters LH positioned closest to the top of the
transmission.
6. Remove the cap screws holding the charge pump
housing against the adjacent pump housing. Using a
seal protector, slide the charge pump housing and
gerotor wheel off of the pump shaft. The O-ring will
probably stay in the groove on the inside of the pump
housing.
NOTE: If a seal protector is not used, wrap the pump
shaft with plastic wrap to protect the seal. When sliding
the housing and gerotor wheel off of the pump shaft, the
drive pin may drop out of the pump shaft. Do not lose
the pin because it is the only part that drives the gerotor
wheel. Without the pin, the gerotor wheel will not rotate;
thus, no "charge pressure" and no hydraulic functions.
7. Examine the gerotor wheel and the inside of the
charge pump housing for excessive wear patterns,
scratches or score marks. If a part is damaged beyond
repair, replace it.
IMPORTANT: If either the gerotor wheel or the
charge pump housing is damaged, replace both
parts. Never replace only one part because the
charge pump housing and gerotor wheel have a
definite wear-in characteristic.
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Groundsmaster 300 Series Page 5 - 31 Repairs