SECTION 21 – TORQUE CONVERTER: GASOLINE VEHICLES
21
DANGER
• See General Warning on page 1-1.
WARNING
• See General Warning on page 1-1.
GENERAL INFORMATION
The torque converter consists of a drive clutch, a driven clutch, and a drive belt. 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. It is in the closed position, and the drive
belt is riding at a high position (large diameter) on it when the engine is at idle.
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 close the drive clutch, pushing the belt up to a higher
position on the 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 provide optimum performance for the OHV engine and powertrain, the vehicle uses a pair of tuned clutches.
To properly assemble and disassemble the torque converter, the following tools should be used:
• Torque Converter Tool Kit (CCI P/N 1014510)
• Scribe or small pick (not included in torque converter tool kit).
TROUBLESHOOTING
See General Warning on page 1-1.
Maintaining proper adjustment of the engine and governor, as well as the torque converter, is essential to the
troubleshooting process. If these adjustments are within specifications and, when climbing a steep hill, the engine
begins to lose RPM before the drive belt reaches the top of the driven clutch, there is a torque converter problem.
If the torque converter is not operating properly, perform the following steps:
2007-2009 Turf 252, Carryall 252 and XRT 900 Maintenance and Service Manual
Page 21-1
