Front axle (4WD) engagement clutch 459/M6921 JCB, aftermarket

For the JCB machines: front axle (4WD) engagement clutch 459/M6921, an aftermarket part.

The clutch is chosen by part number for the gearbox type; the two numbers on the card are versions of the same part. When tracing a fault, also check the solenoid valve that controls the clutch, the pressure and the oil feed rings, as the problem is often not the clutch itself but the circuit supplying its pressure. The clutch wears faster where four-wheel drive is used a lot in hard conditions, so on such machines its pressure is checked at every major service.

Specifications

Compatibility

According to the product card, 459/M6921 is a 4WD engagement clutch. The card also lists 459/M4796, another JCB number for the same part. Fit is confirmed by the part number. The catalogue also has the genuine version of this part. Other parts are in Transmission.

Fitting

The clutch is removed from the output side of the gearbox. Before fitting the new one, renew the oil feed rings and seals and clean the passages. Seat the clutch on its splines without force and tighten the fixings and flange to the specified torque. After assembly, engage and disengage 4WD a few times to check its operation and the clutch pressure.