Torque Convertor Transmission; Drive Belt; Drive Clutch; Operation Of Drive System - Columbia ParCar P4G Service Manual

TORQUE CONVERTOR TRANSMISSION

Operation
Primary Drive
Clutch
At Full Speed
Figure 1 - Operation of Drive System
The torque convertor transmission consists of a primary
drive clutch, a secondary driven clutch, and drive belt. The
primary drive clutch is initially open, totally releasing the
drive belt when engine is stopped. When engine RPM
rises, internal centrifical weights force the primary drive
clutch to close, engaging the drive belt. As engine RPM
continues to increase, centrifical force continues closing
primary drive clutch, forcing drive belt higher between pul-
leys. This is often referred to as "up-shifting."
As accelerator is released, engine RPM is reduced.
Centrifical force on primary drive clutch weights is reduced
and an internal spring forces the drive clutch to open. As
primary drive clutch opens, drive belt lowers between pul-
leys until original position is achieved and engine stops.
When ascending a hill or suddenly increasing throttle
opening, the secondary driven clutch responds to improve
hill climbing or acceleration. The secondary driven clutch
utilizes an internal spring and "cam" device to force the
pulleys closed sufficiently to promote "down-shifting".

Drive Belt

The drive belt is the linkage connecting primary drive
clutch to secondary driven clutch. As the drive belt wears,
engine RPM will increase to compensate for this wear,
maintaining the vehicle's original maximum govern speed.
If the drive belt becomes excessively frayed, glazed, or
worn, it should be replaced. The drive belt is approxi-
mately 1 13/16 inches wide. Remove at its widest point.
After 1/16 inch has been worn from the drive belt (mea-
sured at the widest point), it should be replaced.
Secondary Driven
Clutch
At Start Up
Removal
Caution: Always turn key to off position, remove
key, and disconnect battery negative able before
continuing.
1. Grasp drive belt firmly between primary drive and sec-
ondary driven clutch, lifting briskly to create slack in
belt.
2. Roll the slack in belt over the top edge of secondary
driven clutch.
3. Once freed from secondary driven clutch, slip drive
belt off of primary drive clutch.
Inspection
1. Inspect belt for cracks, splits or frayed cords. Replace
if damage is observable.
2. Check belt width at various points around the belts
diameter. The difference between the widest and nar-
rowest points should not be greater than if the differ-
ence exceeds 1/32.
3. The minimum width of the drive belt is 1 1/16. If the
belt measures less than 1 1/16, replace the drive belt.
Installation
1. Position new drive belt over primary drive clutch, and
pull slack towards rear of vehicle.
2. Slip belt into bottom of secondary driven clutch, and
roll clutch in order that belt drops between pulleys.

Drive Clutch

Removal
Caution:
Turn key switch off, remove key, and
disconnect negative battery cable before
proceeding.
1. Remove drive belt as described in previous section.
2. Loosen (but do not remove) 3 bolts holding
starter/generator to mounting bracket and adjustment
bracket. Push starter/generator down to loosen belt,
and slip belt from pulleys.
3. Remove single bolt holding primary drive clutch to
engine crankshaft.
4. Pull clutch from engine crank shaft, gentle prying may
be required using screw driver or small, thin pry bar.
Use care not to damage starter/generator belt pulley.
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