Genuine Mazda Main Differential Pinion Flange Lock Nut • 0223-27-030

Genuine Mazda 0223-27-030 Main Differential Pinion Flange Lock Nut

Replacement Genuine Mazda differential pinion flange lock nut for Mazda MX-5 Mk1 1.8, Mk2, Mk2.5, Mk3, Mk3.5, Mk3.75 and Mk4 models listed in the compatibility table.

The nut is fitted to the differential pinion shaft and secures the input flange in position. It forms part of the assembly that retains the pinion bearings and preserves the preload established during differential setup.

The component is positioned at the rear differential input flange. There is typically one pinion flange lock nut fitted per differential. This listing is for one Genuine Mazda locking nut.

As a locking fastener used in a critical rotating assembly, the nut should normally be replaced whenever it has been removed. Reusing a damaged, distorted or previously staked nut may compromise its locking action.

• Part type: Differential pinion flange lock nut
• Primary use: Secures the differential input flange to the pinion shaft
• Location: Rear differential input flange and pinion assembly
• Quantity per vehicle: 1
• Quantity supplied: 1 lock nut
• Brand: Genuine Mazda
• Part No.: 0223-27-030
• Also referenced as: 022327030
• Replaces: 9YB1-01-801
• Fitment note: Suitable for MX-5 Mk1 1.8 and subsequent MX-5 generations
• Exclusion: Not suitable for Mazda MX-5 Mk1 1.6 models

Fitment advice: This nut must be used with the correct differential input flange, pinion shaft, lock washer and bearing arrangement. Confirm the original differential type before installation, particularly where a replacement, modified or later differential assembly has previously been fitted.

Other items to consider: When disturbing the pinion retaining assembly, consider purchasing the associated pinion lock washer, pinion oil seal, pinion bearings, bearing races and selective pinion spacer. Fresh manufacturer-specified differential oil may also be required.

Useful tools / consumables: Pinion-flange holding tool, suitable socket, calibrated torque wrench, inch-pound rotational torque wrench, dial indicator, bearing pullers, seal installer, assembly lubricant and manufacturer-specified differential oil.

Difficulty guide: DIY Difficulty: Advanced. Correct installation requires the input flange to be held securely and the pinion-bearing rotational preload to be measured throughout tightening. Simply tightening the nut to an assumed torque can overtighten the bearing assembly and damage the differential.

Why Genuine Mazda? Genuine Mazda differential hardware is designed to match the original pinion-shaft thread, flange, bearing arrangement and locking specification. Correct dimensions and material specification help maintain secure retention and compatibility with the original final-drive components.

What’s in the box: One Genuine Mazda differential pinion flange lock nut, part number 0223-27-030.

Installation notes: Follow the applicable Mazda workshop procedure when removing or installing the differential input flange. Fit a suitable lock washer and new locking nut, restrain the flange correctly and monitor the pinion-bearing rotational preload throughout tightening. Where the differential has been dismantled, verify bearing preload, crown-wheel backlash and gear-tooth contact before filling the unit with the specified oil.