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FORTEC Full Synthetic Differential Oil SAE 80W-140 GL-5 (2 x 1L Bottles) for Mazda RX8 (Series 1 & 2, 2003-2012)

Full synthetic GL-5 lubricant in the correct 80W-140 grade for RX8 rear differential servicing. Two 1-litre bottles supply the full service quantity.

Two angled white RX8 80W-140 gear oil bottles with FORTEC Racing Gear labels

$100

This RX8 80W-140 gear oil is a full synthetic GL-5 differential lubricant. It is supplied as two 1-litre bottles, which is enough to complete a rear differential service on any Mazda RX8 from 2003 to 2012.

A fresh, known-grade fill is the simplest way to keep the rear differential running cleanly. Whether you are buying RX8 differential oil in Australia for a high-mileage Series 1 or a later Series 2, this pack covers the full service volume in one purchase.

FORTEC RX8 80W-140 Gear Oil Features

  • The full synthetic base meets the GL-5 specification required for hypoid rear differentials under load and heat.
  • Two 1-litre bottles provide the complete service volume. You can confirm the full fill before the car is off the road.
  • Rated SAE 80W-140, this viscosity grade matches what the RX8 rear diff demands across hot and cold operating conditions.
  • Finally, coverage across both Series 1 and Series 2 means a single pack suits the full model range from 2003 to 2012, with no variant confusion at the counter.

For RX8 enthusiasts, a deliberate approach to rear driveline maintenance pays off over the life of the car. Draining tired or unknown-grade oil and replacing it with fresh RX8 80W-140 gear oil puts the differential on a clean, correctly specified lubricant. The difference shows up as smoother engagement and less heat buildup under sustained load.

Sourcing Mazda RX8 differential oil in Australia as a complete two-litre pack removes any guesswork about quantity. No partial bottles, no last-minute trips to source an extra litre before the drain plug goes back in.

A driveline service is a good moment to address the gearbox too. The CUSCO Super Sports Gearbox Oil with Neo 2L pairs naturally here, tackling the transmission at the same time as the rear diff. Add the R-MAGIC Super Magnetic Gearbox Drain Plug to capture metallic particles between services and keep both units in better long-term condition. For the full FORTEC lubricant range, visit the FORTEC official site.

Additional information

RX8 Model

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SKU FT-GO-DIF-S1S2 Categories , Types , Brand:

Related RX8 Upgrades

This 80w140 differential oil is one of the best Mazda RX-8 upgrades you can make to your Series 1 (2003-2008) or Series 2 (2009-2012). Differential oil service upgrades are among the top Aftermarket mods you can buy from FORTEC for owners who want better performance and reliability from their RX8. If you are looking for rx8 80w140 diff oil for sale in Brisbane (QLD), Sydney (NSW), Melbourne (VIC), Canberra (ACT), Adelaide (SA), Darwin (NT) or Perth (WA), you’ll find high-quality Japanese Differential upgrades at RX8 Upgrades.

Frequently Asked Questions

How much differential oil does the RX8 rear differential take?

The two-litre pack (two 1-litre bottles) is sized as a practical service quantity for the RX8 rear differential. Having the full two litres on hand before draining the existing fill means the job is not interrupted waiting for more oil.

Is 80W-140 the correct grade for the RX8 differential?

The 80W-140 GL-5 grade is the specification this oil is supplied in for RX8 rear differential servicing. If you are unsure whether this grade matches your specific build or usage, cross-check against your workshop manual or a trusted RX8 specialist before filling.

What does GL-5 mean and why does it matter for a differential?

GL-5 is a gear oil performance classification that denotes a lubricant formulated to handle the high-pressure, high-load conditions found in hypoid rear differentials. The RX8 rear differential operates under significant heat and load, making the GL-5 rating the appropriate specification for that application.

Is this differential oil suitable for both Series 1 and Series 2 RX8 models?

Yes, this 80W-140 GL-5 full synthetic differential oil is listed for both Series 1 (2003-2008) and Series 2 (2009-2012) RX8 models, covering the full production run.

Why choose a full synthetic over a conventional differential oil for the RX8?

A full synthetic formulation offers greater thermal stability and resistance to breakdown under the heat and load cycles that a rear differential experiences, particularly during spirited driving. It provides a known, consistent lubricant grade rather than relying on an ageing or unknown existing fill.

Why is the oil supplied as two separate 1-litre bottles rather than a single 2-litre container?

The two-bottle format lets you account for and measure the lubricant easily before the car is off the road. It also means you can confirm the full quantity is on hand before draining the differential, avoiding any delay mid-job.

How often should the RX8 rear differential oil be changed?

Differential oil service intervals vary depending on usage and driving conditions. For a definitive interval, consult the Mazda RX8 workshop manual or a qualified RX8 specialist, particularly if the car sees track use or has covered high kilometres on an unknown existing fill.