Gear box oil/ diff oil capacitys

Hi is there a guide or section with all the different fluid capacitys? I’ve got a mk 3.75 1.8 5 speed ,I’ve changed the engine oil now going to do the diff and gear box but want to know how much of each I need ? Thanks

Buy 2 x 1ltr bottles for gearbox and 1 x 1 ltr for the diff.
The above will do both jobs and you’ll have a very small amount of each left after doing both.

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Thanks mick any preferences for what people use ? I see its 75w 90 for both though the diff needs 75w 90 GL5 whatever that means

My preference…
Castrol 75w 90 Syntrans for gear box and Castrol 75w 90 Universal oil for the diff. You are correct that the diff should be spec GL5



I have emailed opie and they gave me a selection just was unsure on quantitys, but if 2l for gear box and 1l for the diff is correct thats great thanks.

Yep 2 litres will do the 5 speed, 6 speeds need a little over 2 litres, I’ve done oil changes on both models.
The diff the same on all, just under 1 litre.

Thanks mate

recommend bleeding the clutch while you’re underneath

Whys that Mike?

If clutch fluid is old a change is a goid idea tbf. And brake fluid. It’s hydrostatic so attracts and absorbs water. It performs better when new not to mention water can corrode the cylinders and cause them to seize apparently.
Opie oils are a great company. I’ve used them for 20 years I bet, always knowledgable and helpful.

Mk3.75 brake and clutch fluids share the reservoir.

No point in doing one without doing the other.

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The cars done 40,000 miles and its had brake fluid change in this time though that doesn’t mean the clutch would have been bled I guess,what sort of job is it ? Are there step by step guides for all these things on the forum somewhere?

as stated below, worth doing (with the brakes) , but the clutch bleed is right next to the gearbox filler, so whilst you are underneath, not sure if you’ve access to a hoist? or got to jack / crawl, so worth doing whilst you’re down there. made my clutch and brakes feel nicer. can’t say noticed much difference doing the box and the diff, (also checked the “turret”)

I’ve got use of a ramp which is great, I’ll look into doing this aswell thanks guys.