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"Transmission Fault" warning light came on and car's transmission went into limp mode and transmission functioned poorly.

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In the event of “Transmission Fault” following things need to be checked

Gear shifting: Driver gear selection is transmitted from the gear selector lever by cable to a lever fitted to a selector shaft in the transmission casing. This shaft moves the manual valve and the rotary switch. The rotary switch signals all gear positions except D to 4. A separate switch in the driver gear selector mechanism detects movement of the selector between D and 4. The communication of driver gear selection to the TCM is made by the rotary switch. Gear shift points are selected by the TCM in response to output speed, engine load, selector position, accelerator pedal position and driver mode selection. Driver control of the shifting is via the selector lever, throttle pedal position, kick down switch and mode switch. Two shift modes are available, sport and normal, controlled by the driver from a switch on the gear selector surround. During kickdown, gear upshifts occur at 6800 RPM engine speed.

Mechanical Description: The unit is an oil filled-for-life system therefore no dipstick is fitted to the transmission. A filling/level plug is located at the right-hand side rear of the casing for service oil level checking and replenishment, if required. To achieve effective cooling, the oil is pumped from the transmission casing at the front left-hand side of the casing to the car mounted oil cooler. The oil is returned from the cooler to the inlet connection on the front right-hand side of the casing. The cooler is a plate-type design made from aluminum and is located in the car radiator outlet tank. To detect changes in oil viscosity which occurs as the oil temperature changes, an oil temperature sensor is located in the unit casing sump. Also located in the transmission casing are the input shaft speed sensor (turbine speed) and output shaft speed sensor (vehicle speed). The torque converter is a lightweight unit which, because of its low mass, improves engine responsiveness. The torque converter bell housing is bolted to the transmission casing. Mounting of the transmission is conventional by bolting the torque converter bell housing to the engine. The rear extension housing is bolted to the transmission casing and forms the rear engine/transmission mounting point. It also carries the output shaft oil seal. The electro-hydraulic module contains three solenoid valves and five pressure regulators for gear shifting. Each of the three solenoid valves control the flow of transmission fluid to the selected clutches. One pressure regulator serves as master pressure control for the entire system and one is used exclusively for torque converter clutch lock-up operation. Replacement transmission units are shipped complete with the torque converter and housing, extension housing, coupling flange and rotary position switch. They are also fully filled with 10 liters (2.645 US. gals) of oil. Consequently, when undertaking a transmission replacement, oil replenishment should not be necessary. The exterior of the transmission is coated with non-drip corrosion protection oil, which must not be mistaken for an oil leak.

Electrical Connections

Bayonet Connector: A round, 16-pin, bayonet electrical connector is fitted at the rear left-hand side of the transmission which communicates with the 5 pressure regulators, 3 shift solenoids, oil temperature sensor and the input and output.

Automatic Transmission: The five-speed automatic transmission is designed to accommodate different driving styles and automatically adapt shift patterns to suit varying road/driving conditions. The switch marked .S. on the .J. gate surround enables the driver to select either normal .N. or sport .S. transmission modes.In addition to the .switched. Transmission modes (.N. and .S.) the transmission control module will select shift patterns to suit specific conditions. These are:

Cruise Control. When cruise control is operating at set speed the transmission selects a shift pattern to suit cruise control operation.

Traction Control. When traction control is switched ON and the system is activated, the transmission selects a shift pattern to suit traction control conditions.

Gradients. When the vehicle is being driven on roads with uphill gradients, the transmission selects a shift pattern designed to make better use of engine power and aid engine cooling.

Note: Under the conditions described above, the relevant transmission mode will override the .N. or .S. modes selected by the driver. When such conditions no longer exist, e.g. Cruise Control switched OFF, the transmission will revert to the shift pattern previously selected by the driver, i.e. .N. or .S..

Please do accept this solution and revert for further assistance.



Posted on May 30, 2009


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