Torque converter 04/600785 JCB, OEM

Torque converter 04/600785 is an OEM part for the JCB machines.

The torque converter is a hydraulic coupling between the engine and gearbox: the impeller turned by the engine drives oil onto the turbine, and the stator between them redirects the flow to multiply torque at low speed. That lets the machine pull away smoothly without a clutch pedal, keeps the engine from stalling when stopped under load and increases tractive effort as the bucket enters the pile. Signs of failure are loss of pulling power, overheating transmission oil, stall-test engine speed outside the limits and metallic noise from the converter. Wear debris is carried into the gearbox with the oil, so a fault should be caught early. The converter's condition can easily be judged with a stall test: holding the machine on the brakes in forward gear, apply full throttle and compare the engine speed with the service value.

Specifications

Compatibility

According to the product card, 04/600785 is a torque converter. The card also lists 04/600868. Fit is confirmed by the part number. Other parts are in Transmission.

Fitting

The converter comes out once the gearbox is separated from the engine. Before fitting the new one, pour some clean transmission oil into it and push the hub in while turning it until it engages fully with the pump drive; a converter not fully home can break the pump when the engine is bolted up. Tighten the drive plate bolts to the specified torque. After assembly, top up the oil, let the engine idle so the converter fills, then carry out the stall test and pressure checks.