Automatic gearbox - Jatco (6): Description and operation

Fluid Cooler Td4 (Cold Climates)

6

5

M44 1675

1 Gearbox fluid feed pipe 2 Gearbox fluid return pipe 3 Mounting bracket

1

2

3

4

4 Engine coolant feed hose 5 Radiator bottom hose 6 Engine coolant return hose

The fluid cooler is located on a bracket at the front of the gearbox and is similar in design to the KV6 fluid cooler. The Td4 cooler has a larger capacity than the KV6 cooler for additional cooling required with the diesel engine and is mounted on a different design of bracket.

The cooler comprises cores which allow fluid to flow across from one side of the cooler to the other. Each core is surrounded by a water jacket which allows engine coolant to flow around the cooler.

The cooler receives its coolant supply from the radiator bottom hose. The radiator bottom hose has two smaller hoses connected to it which in turn are connected to the cooler. Between the two smaller hoses, in the radiator bottom hose, is a spring loaded valve. The valve opens and closes with changes in coolant pressure, diverting coolant from the bottom hose, through the cooler via the upper hose connection. The coolant exits the cooler through the lower connection and flows back into the bottom hose, downstream of the spring loaded valve.

The cooler is connected to the gearbox by metal pipes and flexible hoses. The gearbox fluid flows from the gearbox to the RH connection on the fluid cooler. The fluid then flows through the cores in the cooler which are surrounded by engine coolant which cools the gearbox fluid. The fluid exits the fluid cooler via the LH connection and is returned to the gearbox.

The engine coolant flows from the engine oil cooler into the upper coolant connection on the fluid cooler. The coolant exits the cooler via the lower connection and flows to the thermostat housing.