Bold reference numbers in this section identify parts not shown in the figures alongside the text, but which can be found in the exploded view diagram.

Restrain the primary driving gear (B) using service wrench no. 88713.2423 and unscrew the threaded nut (5) securing the pinion.

Remove the primary driving gear (B) using puller 88713.2092 and interposing a packing piece of aluminium or copper between the crankshaft and the screw of the puller.

To check the gear backlash, temporarily fit the clutch drum (1) complete with internal spacer (4), driven gear (A), roller bearing (3) and internal bush (2) on the gearbox primary shaft. Fix a dial gauge to the engine crankcase, positioning the stylus against a gear tooth.

Turn the driven gear (A) to mesh the teeth and check with the dial gauge that backlash ranges between 0.05 and 0.07 mm.

Repeat the check at 16 different points of the driven gear.

If the measured values are outside the permissible tolerance limits, try changing the position of driven gear (A) on the primary shaft, leaving the driving gear (B) on the crankshaft. If the backlash is still outside the tolerance limits, renew the primary drive gear pair (1).

After checking the gear backlash, secure the pinion (B) with the service tool part no. 88713.2423, apply the recommended grease to the ring nut (5) and tighten it to a torque of 190 Nm (Min. 171 Nm - Max. 209 Nm) (Sect. 3 - 3, Engine torque settings).

Refit the oil pump and check the clearance between the oil pump gear and primary drive gear on the crankshaft (Sect. 9 - 2.1, Refitting the oil pump).

Fit the internal spacer (4) to the input shaft with its flat side facing outwards. Install the inner bush (2) and clutch drum (1) with driven gear (A) complete with roller bearing (3).