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- ViscositySpecifications
Buy 75W-80 gear oil
75W-80 is the thin manual gearbox oil: made for gearboxes that are meant to shift easily even in the cold. It is specified above all by the French manufacturers as well as by some Ford and Opel gearboxes - and where it is specified, nothing thicker belongs in there either.
Why some gearboxes call for a thinner oil
A manual gearbox is not just lubricated, it is also operated. The synchro rings have to match speeds at every gear change, and the stiffer the oil, the more resistance the hand feels at the lever - especially in the first few minutes after a cold start.
Gearboxes designed around 75W-80 shift measurably more heavily on a 75W-90, without anything breaking in the process. The reverse case is the critical one: a gearbox that calls for a 90 gets a thinner lubricant film than intended with a 75W-80.
Where it is specified
- many manual gearboxes from Peugeot, Citroën and Renault
- parts of the Ford and Opel range
- individual gearboxes from other manufacturers, usually with their own approval number in the manual
Go by the manufacturer approval, not just the grade: French gearboxes often have their own numbers in the maintenance schedule, and those belong on the container.
GL-4 is the rule here
75W-80 is a manual gearbox oil, which makes API GL-4 the normal case - matched to brass synchro rings. A GL-5 oil belongs in final drives, not here, even where it is offered in the same viscosity. For axles in our range: 75W-90 and 80W-90.
Changing
The fill quantity on car manual gearboxes is usually between 1.5 and 2.5 litres, so one to three 1-litre bottles. A change is rarely provided for in the service schedule, but it helps measurably where a gearbox shifts stiffly when cold and the clutch has been ruled out as the cause - there it is worth trying before bigger work is due.
We take back used oil in the quantity purchased, gear oil expressly included (used oil disposal).
Frequently asked questions
Can I fill 75W-90 instead of 75W-80?
Nothing breaks from it, but the gearbox shifts more heavily when cold - exactly the effect the thinner grade is there to avoid. If your maintenance schedule calls for 75W-80, stay with it.
Does an oil change help against stiff shifting?
Often yes, if the gearbox is only stiff when cold and the clutch is in order: aged gear oil turns viscous and carries debris. It is a cheap thing to try before work is done on the gearbox itself - a guarantee it is not.
