Can I use 75w90 instead of 75W Toyota?

Generally not automatically. 75W-90 is a gear oil viscosity grade used for manual transmissions and differentials, while “75W” as a standalone engine oil designation is not a standard modern engine oil grade. Whether you can substitute depends on the exact Toyota specification for your model and component. Always check the owner's manual or ask a Toyota dealer before making a substitution.

Understanding the oils: engine oil vs gear oil

The numbers in 75W-90 describe viscosity characteristics for gear oils used in transmissions, transfer cases, and differentials. Engine oils use a different rating system (for example, 0W-20, 5W-30). Using the wrong type of oil can cause excessive wear or shifting problems, so it’s important to match the specification to the component the oil is meant to service.

Before you consider a substitution, it helps to know where each oil type is used in a Toyota vehicle and what the exact specification requires for that component.

When 75W-90 is appropriate in a Toyota

Use 75W-90 only if the vehicle’s manual or service data calls for that exact gear oil specification for a specific component (such as a manual transmission or certain differentials). In these cases, choose a 75W-90 that meets the required rating (for example, API GL-4 or GL-5 as specified, and any Toyota-specific additive or friction-modifier requirements).

Important caveats include not using 75W-90 in automatic transmissions (which require Toyota ATF) or in CVTs (which require Toyota CVT fluid), and not using gear oil in engine oil applications. Always verify the precise specification for your model year and drivetrain.

Before substituting, confirm the exact component and spec the manufacturer requires. If the manual calls for 75W-90, ensure the fluid meets the correct GL rating and any Toyota-specific requirements.



• Manual transmissions or certain differentials may specify 75W-90 with a GL-4 or GL-5 rating. Do not substitute unless the spec explicitly allows it and the oil meets the required rating.


• Automatic transmissions require Toyota-specific ATF (not gear oil) and a different viscosity/chemistry. Using 75W-90 in an automatic transmission can cause shifting problems or damage.


• CVTs require dedicated CVT fluid from Toyota or a compatible specification. 75W-90 is not suitable for CVTs.


• Some differentials with limited-slip clutches may require a gear oil with friction modifiers. If the vehicle calls for a specific modifier, use one that includes it.

Conclusion: 75W-90 can be appropriate in Toyota vehicles only when the exact component calls for that gear oil grade and specification. Do not apply it by assumption to engines, automatics, CVTs, or unrelated systems.

Practical steps to verify the correct oil for your Toyota

To avoid costly mistakes, follow these steps to determine whether 75W-90 is acceptable for your vehicle.

1. Check the owner's manual or official service data for the exact oil specification required for the component in question (engine, manual trans/diff, automatic trans, CVT).


2. Identify the component affected by the oil decision (engine, manual transmission, automatic transmission, CVT, differential, or LSD).


3. Confirm the required viscosity (for example, 75W-90) and the exact rating (GL-4, GL-5, or any Toyota-specific standard).


4. Ensure the oil you choose is not only the right viscosity but also carries the correct ratings and any additive requirements specified by Toyota.


5. Avoid mixing different oil types or viscosities in the same system unless the manual explicitly allows it.


6. When in doubt, consult a Toyota dealer or a qualified technician to confirm the correct fluid for your model/year.

Conclusion: By verifying the exact Toyota spec for your model and component, you can confidently determine whether 75W-90 is permissible or if a different fluid is required.

Summary

In short: 75W-90 is not a universal substitute for Toyota’s “75W” specification without explicit approval in the vehicle’s documentation. Engine oil grades and gear oil grades serve different systems, and Toyota designates fluids by specific needs for each component. Always reference the owner’s manual or dealership guidance, and use the exact fluid type, viscosity, and rating specified for your vehicle. If you cannot locate a clear recommendation, err on the side of caution and seek professional advice.

What is the difference between 75w and 75W90?

75w - 90 means that when that oil gets hot it gets thinner than a 75w .

Can you use 75W90 instead of 75w85 Toyota?

Yes, you can use 75W-90 instead of 75W-85 in a Toyota, as the viscosity difference is small and 75W-90 is widely available. Ensure the new fluid meets the recommended GL-5 rating specified by Toyota, as the GL (gear lubrication) rating is more critical for the internal protection of your differential than the viscosity difference. 
Why it's okay to switch

• Small viscosity difference: 75W-85 is a slightly thinner oil when hot than 75W-90, but the difference is not significant enough to cause damage, especially in a non-towing scenario. 
• Availability: 75W-85 is often harder to find than 75W-90, which is a standard and readily available weight. 
• Consistent with dealer practice: Many Toyota dealerships use 75W-90 when a vehicle calls for 75W-85, according to user reports. 

Important considerations

• Check the GL rating: The most crucial factor is the fluid's GL rating. Always use a fluid with the correct rating, such as GL-5 for most differentials, as recommended in your owner's manual. 
• Avoid 75W-140 for standard use: While 75W-140 is thicker and sometimes recommended for heavy towing, it is generally not necessary for normal operation. 
• Manual transmissions: Be cautious with manual transmissions, as they may have different fluid requirements. Some older Toyota manual transmissions might require a GL-4 specific fluid, and using a GL-5 fluid can cause premature wear. 

What happens if you put the wrong gear oil in your differential?

Using the wrong differential fluid can lead to poor lubrication, overheating, increased wear and tear, and eventual differential failure. This is because incorrect fluid won't provide the necessary friction modifiers, viscosity, or other properties, causing gears to grind and clutch packs to overheat and burn. Eventually, this can lead to costly repairs or the need for a complete replacement of the differential assembly. 
Immediate and long-term consequences

• Overheating: The wrong fluid can't properly cool the gears and bearings, leading to overheating and a burning smell. 
• Increased wear: Without the correct lubrication, gears and bearings will grind against each other, accelerating wear and tear. 
• Noise: A sign of improper lubrication is whirring, howling, or grinding noises, especially when turning. 
• Reduced performance: You may experience poor road grip, vibrations, or resistance when turning. 
• Differential failure: In severe cases, the lack of proper lubrication can lead to a complete seizure of the differential, requiring an expensive replacement. 

What to do if you've used the wrong fluid

• Stop driving the vehicle immediately to prevent further damage. 
• Have the differential professionally flushed and refilled with the correct fluid specified by your vehicle's manufacturer. 
• Be aware that damage may have already occurred and flushing may not be enough to reverse it. 

What kind of oil does a Toyota diff take?

Genuine Toyota Differential Gear Oil 85W-90 GL-5 4 Litres.