Section 17 - Torque Converter; General Information - Pioneer 1200 Maintenance Service Manual

SECTION 17 – TORQUE CONVERTER
∆
DANGER
• See General Warning, Section 1, Page 1-1.
∆
WARNING
• See General Warning, Section 1, Page 1-1.

GENERAL INFORMATION

The torque converter consists of a drive clutch, a driven clutch, and a drive belt. To provide optimum perfor-
mance for the OHV engine and powertrain, the vehicle uses a pair of tuned clutches.The drive clutch, which
is mounted to the engine, is in the open position when the engine is at idle. At this point, the belt is riding at a
low position (smaller diameter) on the drive clutch. The driven clutch is mounted on the transaxle. When the
engine is at idle, the driven clutch is in the closed position, and the drive belt is riding at its highest position
(large diameter).
At the point of clutch engagement, the speed ratio of the drive clutch to the driven clutch is 3.5 to 1. This ratio
provides excellent starting and low-speed torque.
As engine speed increases, centrifugal force on internal weights closes the drive clutch, pushing the belt up
to a higher position on the drive clutch (increasing the diameter of the belt loop). As the diameter of the belt
loop increases at the drive clutch, the driven clutch is forced open as the diameter of its belt loop decreases.
At governed top speed, the ratio of drive clutch to driven clutch is 0.92 to 1.
On steep grades, or when the vehicle is heavily loaded, higher torques are achieved through the use of a
torque-sensing ramp device on the driven clutch. This device overcomes the force of the centrifugal weights
to close the driven clutch and open the drive clutch, thus increasing axle torque with little or no change in
engine RPM.
The engine and torque converter rotate clockwise as viewed from the clutch side of the engine.
To properly assemble and disassemble the torque converter, the following tools should be used:
• Torque Converter Tool Kit (CCI P/N 1014510) (Figure 17-1, Page 17-2)
• Scribe or small pick (not included in torque converter tool kit)
2003 Pioneer 1200/1200SE Gasoline Vehicle Maintenance and Service Manual
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Page 17-1