Have you got the active bonnet actuators on your car?
Yep all that. 
Most major oil companies have a recommendations section on their web site. It will be near their home page; you just enter your registration number and it shows you the correct oils for your car from their range of oils.
Thanks MickAP, just so I understand, it looks like the same oil for the LSD and gearbox (the two you show in your picture on the right are the same oil but the name has changed). Is that right? So long as they are GL4 specification it is good to go for both applications?
It would appear so looking at my Mazda manual. It says 75w 90 GL4 for gearbox and 75w 90 GL4/5 (meaning 4 or 5) for the diff I read it. Keep to those specs whatever the brand and thatāll do the job.
Iāve alway bought the different oils as you see in the picture, I guess just the one oil will do both for diff/gearbox.
The confusion (well for me) is whenever I go to buy any diff oil or gearbox oil (Castrol) the packaging and description has changed. The diff oil went from multivehicle to universal now itās Transmax. The gear oil has changed names too over the years.
Anyways thatās just Castrol, a brand Iāve always used from day one of owning MX-5ās around 12 years ago.
You can buy whichever brand suits just check that GL spec against your manual spec and your good to go.
I still donāt know why as in the above posts the same car basically from the same year range their manuals read different for the spec of gear oil to use.
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No wonder there is confusion out there and, what I thought would be a simple post, has generated 25+ responsesā¦
The differential is the final drive aspect of gearing and will therefore have the maximum load to distribute etc. Therefore will need more Extreme Pressure requirements. (Hence Mazda states GL4/5). GL5 in my manual!
There are no soft metals in there like a gearbox so I would stick with a GL5. 
As a matter of interest what does your manual state?
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You go and find some Castrol gear oil off the shelf, around me no one sells it. Halfords donāt stock it and I used to get mine from B&Q, they stopped selling it.
So itās over to the internet, Opie oils or eBay sellers.
Wilko used to sell Mobil engine oil of the spec I wanted, again they no longer stock it, so internet again. I tried Halfords, they only had there own brand and a few others, no Mobil of the spec I wanted.
And they say shop local or itāll kill the high street.
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Thanks for your help.
My manual states:
Transmission: GL-4 or GL-5 SAE 75w-90
Rear diff: GL-5 SAE 90
Engine oil: range but 5w-30 looks right for UK (API SL,SM or ACEA A3/A5)
Same as mine then. 
Just wondering, āPerhapsā Mazda realised that the GL5 is not good for the 6 speed transmission.
As perhaps many others have.
Then amended the manual.
I usually do all the oils when buying another car. The engine and diff oils have been changed by me on this latest NC (the diff didnāt need it TBH) I found out afterwards it was done within the last 18 months along with the gearbox oil.
I know what spec diff oil is in and engine oil too now, probably had before who knows, now Iām thinking what gearbox oil is in?
It has full Mazda service history so why worry. But thatās me I do wonder, especially when I asked a dealer once (not Mazda) a few years ago, what engine oil do you use, the reply was "the stuff in the big drum in the workshop"
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āHi,
Is there a single point of reference for all lubricants for my 2.0 Sport NC? I am after, recommendations for LSD, Gearbox and Engine oil.
Thanksā.
I thought that was quite a sensible request which the ācurrent usersā have answered. We then make up our own mind then what to use.
- Untrained members of the public. What on earth is that supposed to mean?
We are all registered users on this Forum with a wealth of life time experience, training, Diy, recommendations, (Good and Bad) knowledge and qualifications perhaps on many different aspects and subjects. Which is why Forums (a meeting or medium where ideas and views on a particular issue can be exchanged) are a very good source to gain information.
Letās be honest, their is some pretty shoddy work still being done out there by āTrainedā people. Thankfully in the minority.
- Unscientific. None of us really know the exact chemical/ingredient make up of any lubricant and thus have to rely on the type approval and specification on the labels. As already stated by several, the Manufacturers of the oils will also recommend lubricants specific to each model. Data sheets will actually tell you nothing about what science or chemicals that have been used for obvious reasons.
I personally would not recommend ANY lubricant/oil to anyone that did not have the Type Approved Specification clearly marked on the can/label.
Unless you know differently and have your own laboratory and a science degree in Automotive lubricants perhapsā¦
- Do you know then, why Mazda changed the 6 speed gearbox/transmission oil specification in the MX5 NC 3.75 from GL4/GL5 to ONLY GL4 in the 2014 model year?
As reggie747 said, ātime to chip in eh and enlighten us all perhapsā with your wealth of knowledge.
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The same questions get asked day in, day out so I wrote a guide here:
and a lot more here: http://www.duratecnc.co.uk/?cat=1
Or briefly:
For engines put a fully synthetic in to Mazdas recommended grade, diff as per Mazda.
If you like your gearbox notchy when cold put whatever you like in as long as itās GL4 in a 6spd. You can put a GL4 or 5 in a 5spd
If you want a smoother gear change then buy our oil.
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So my untrained, unscientific answers to the questions posed were pretty much spot on.
I could recommend a few chocolate bars too but they arenāt really good for your health.
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Exactly my thoughts.
My trained āunscientificā answers were the same.
Donāt care what anyone else states, you are trained!
We need people like you, (and many others on here) to pass on their lifetime wealth of knowledge of the MX5ās to help others.
All the best.
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Just a little spanner to throwā¦
Castrol gearbox oil comes in various flavours of the same spec, there is one that meets Ford spec, and another that meets VW specs.
I doubt they are the same chemically, but they may be identical and this is just marketing spin. That said, it is the Ford flavour in my car.
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To be fair, and I do not know DuratecNC, he does have a business to run, and whilst he offers advice, he does not push what he sells.
The link he posted just about says it all and is a worthwhile read.
I am happy to look at any guidance offered, so if I am ever looking at having my gearbox oil replaced, I would not rule out a trip to Batley. I would simply weigh up my options and then make a decision based on what I have read elsewhere.
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I can recommend DuratecNCās gearbox oil. 2.0l sport 6 speed, was notchy now itās not. Good stuff
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