Automatic gearbox - Jatco (Fluid Cooling): Description and operation

Fluid Cooling

Fluid cooling is performed by a dedicated fluid cooler for the gearbox. On KV6 and Td4 cold climate models, a water cooled fluid cooler is located at the front of the gearbox. On Td4 hot climate models an air blast cooler, which replaces the water cooled cooler is located in the front LH wheel arch.

Fluid Cooler KV6

Cooler from all except NAS and Gulf States models shown; cooler for NAS and Gulf States models similar

1 Gearbox fluid feed pipe 2 Gearbox fluid return pipe 3 Engine coolant feed hose

4 Engine coolant return hose 5 Mounting bracket 6 Fluid cooler

The fluid cooler is located on a bracket at the front of the gearbox. 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 is connected to the gearbox by metal pipes and flexible hoses, and to the engine cooling system by coolant hoses.

The gearbox fluid flows from the gearbox to the upper 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 lower connection and is returned to the gearbox.

The engine coolant flows from the engine oil cooler (on all except NAS and Gulf States models), or the cylinder block (on NAS and Gulf States models), to the lower coolant connection on the fluid cooler. The coolant exits the cooler via the upper connection and flows to the thermostat housing.