Clutch piston (transmission) 459/M2179 JCB, aftermarket

For the JCB machines: clutch piston (transmission) 459/M2179, an aftermarket part.

The clutch piston works inside a clutch drum in the gearbox: when a gear is selected, pressurised oil enters the drum, the piston moves and squeezes the friction and steel plates together, and the clutch locks; when pressure is released, return springs push the piston back. Seals on the piston hold the pressure. A cracked piston, worn seal grooves or a piston sticking in the drum lead to incomplete locking, slipping, burnt plates or a gear that does not fully disengage. If the piston returns slowly or sticks, check the strength of the return springs and the drum bore.

Specifications

Compatibility

According to the product card, 459/M2179 is a clutch piston. The card also lists 459/10096, 459/M2170, which are other JCB numbers 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

On assembly, wet the piston seals with clean transmission oil and push the piston into the drum squarely without cutting the seals. Fit the return springs and retaining circlip using a suitable press. Soak the plates in oil, stack them in order and measure the pack clearance. After the gearbox is assembled, check the clutch pressures with a gauge.