Genuine Mazda Gearbox / Differential Drain Plug Sealing Washer • 99564-1800

Genuine Mazda 99564-1800 Gearbox / Differential Drain Plug Sealing Washer

Replacement Genuine Mazda sealing washer for Mazda MX-5 Mk1, Mk2, Mk2.5, Mk3, Mk3.5, Mk3.75 and Mk4 models.

This washer is used beneath compatible gearbox, differential, transfer or related drivetrain drain and filler plugs where Mazda specifies this reference.

When the plug is tightened, the washer compresses between the plug and casing to create an oil-tight seal. Correct sealing helps retain the lubricant and prevents dirt or moisture entering around the plug.

The washer should normally be renewed whenever the applicable drain or filler plug is removed. A previously compressed, distorted, corroded or heavily marked washer may not reseal reliably when reused.

This listing supplies one Genuine Mazda sealing washer only. The associated drain or filler plug is not included.

• Part type: Drain / filler plug sealing washer
• Mazda catalogue description: Washer / gasket
• Primary use: Seals compatible gearbox and differential drain or filler plugs
• Location: Gearbox, differential, transfer or related drivetrain casing, depending on application
• Quantity required: Normally 1 per applicable plug
• Quantity supplied: 1 sealing washer
• Drain or filler plug included: No
• Brand: Genuine Mazda
• Part No.: 99564-1800
• Also referenced as: 9956-41-800 / 995641800
• Fitment note: Use only where this Mazda washer reference is specified for the fitted gearbox or differential

Important: Mazda uses several visually similar sealing washers across its gearbox, engine and differential assemblies. Confirm the washer reference required for the exact plug and casing before installation.

Fitment advice: This washer is confirmed across Mazda MX-5 drivetrain applications, but the exact drain or filler position can vary by generation, transmission and differential type. Where a replacement gearbox or differential has been installed, compare the existing washer and plug arrangement before ordering.

Other items to consider: When carrying out a gearbox or differential oil service, consider purchasing the correct lubricant and replacing any damaged drain or filler plugs. Inspect the casing threads, plug sealing face, breather and nearby oil seals for leakage.

Useful tools / consumables: Suitable socket or spanner for the applicable plug, ratchet, torque wrench, drain container, fluid pump, cleaning brush, lint-free cloths and the manufacturer-specified gearbox or differential oil.

Difficulty guide: DIY Difficulty: Easy. Replacement is normally undertaken during routine drivetrain oil servicing. The vehicle should be raised and supported safely and remain level where an accurate lubricant level must be established.

Why Genuine Mazda? Genuine Mazda sealing washers are manufactured to match the original plug diameter, sealing face and casing arrangement. Correct dimensions and material specification help the washer compress evenly and provide a reliable fluid seal.

What’s in the box: One Genuine Mazda gearbox / differential drain or filler plug sealing washer, part number 99564-1800.

Installation notes: Clean the plug, sealing face and surrounding casing before installation. Remove the old washer completely and inspect the plug and casing threads for damage. Fit the new washer, tighten the plug to the Mazda specification applicable to that exact assembly, refill with the correct lubricant and inspect for leakage after servicing.