Gear box oil/ diff oil capacitys

Technical Area Routine Servicing
1

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

2

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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3

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

4

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

Gearbox…

Diff…

5

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.

6

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.

7

Thanks mate

8

would
recommend bleeding the clutch while you’re underneath

9

Whys that Mike?

10

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.

11

Mk3.75 brake and clutch fluids share the reservoir.

No point in doing one without doing the other.

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12

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?

13

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”)

14

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

16

I have a 2012 plate nc2 with 45k on the clock. Very good service history but no sign of a change of gear box or diff oils. Anyone know what Mazda’s recommendation is on frequency of change of these fluids?

17

4 years or 50,000 miles for the diff and 5 years or 62,500 for the gearbox. It’s in the Scheduled Maintenance section of the Owner’s Manual if you have one.

18

Thank you for that Roadster_Robbie. So, in a word, I need to get the gear box oil changed straight away - correct? Consensus seems to be to use a syntrans multivehicle 75W/90 GL4, would that be a good choice and hopefully make first and reverse gear selection and movement up and down the box easier?

19

Yes the Syntrans, or whatever they call it now, anyways Castrol 75w 90 GL 4 is the important spec. Many other offerings (brands) available, probably the cold weather plays a part in a notchy change, 1st to 2nd mainly. Give it a few hundred miles after the oil change to probably feel any improvement, don’t expect miracles though.