Transmission shims 921/52900 JCB, aftermarket

For the JCB machines: transmission shims 921/52900, an aftermarket part.

Shims are chosen by part number for the gearbox type and adjustment point, and their diameter and thickness range must suit the location. The total thickness of the shims removed on strip-down is measured and noted, but whenever new bearings or gears are fitted the adjustment must be done again, as new parts come with their own tolerances. A taper bearing run with the wrong preload either overheats or runs slack, and in both cases the bearing and gears wear early. The right shim combination removes that risk and keeps the gearbox quiet.

Specifications

Compatibility

According to the product card, 921/52900 is a shim set. Fit is confirmed by the part number. Other parts are in Transmission.

Fitting

Select the shim thicknesses by measuring with a micrometer and do not use burred or bent shims. Fit them clean and oiled, and after assembly measure the end float or bearing preload (rolling torque) and compare it with the manual. If it is out, change the shim combination and measure again. In the first hours after the repair, watch the transmission oil temperature and level, and do the first oil and filter change earlier than usual.