Automatic gearbox - Jatco (1): Description and operation

Air Blast Fluid Cooler Td4 (hot climates)

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2 4

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3

9

M44 1674

1 Mounting bolt (3 off) 2 Air blast cooler 3 Temperature sensor 4 Sensor and fan connector 5 Harness connector

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5

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6

3

8 7

6 Gearbox fluid feed pipe 7 Gearbox fluid return pipe 8 Quick release connections 9 Electric fan

The air blast cooler is located on the front LH wheel arch in place of the Fuel Burning Heater (FBH) and is fitted to models for climates of 50°C (122°F).

The air blast cooler is a cross flow type cooler with end tanks at either side. A boss on the outer tank houses a temperature sensor which controls the operation of an electric cooling fan attached to the forward face of the cooler. The boss also provides for the gearbox fluid feed and return connections.

The front bumper on these models is modified to allow for the additional air flow required to pass through the cooler matrix. An aperture in the front LH corner of the bumper allows intake air to flow to the cooler. The air flow is directed by a duct at the rear of the bumper into the cooler matrix. The LH wheel arch liner on these models has louvres to aid the air flow through the matrix.

The electric fan is connected to the temperature sensor which in turn is connected to the harness multiplug used for the FBH in other markets. The power supply is permanent allowing the fan to operate after the ignition is switched off. The sensor activates the fan when gearbox fluid temperature in the cooler reaches approximately 100°C (212°F).

The air blast cooler is connected to the gearbox with metal pipes and flexible hoses. Two quick release couplings are provided to ease cooler removal. The cooler and associated pipes require an additional 0.7 litre of automatic transmission fluid.

Sensors

The EAT ECU sets correct gear change scheduling using three speed signal inputs: intermediate speed, turbine speed and vehicle speed in conjunction with a throttle position signal from the ECM.