Trans and Diff oil bought from MX5 Parts. Negative reviews on their site has put me off using it

Technical Area Routine Servicing
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  1. My model of MX-5 is: __1997 1.6 90 BHp NA
  2. I’m based near: __Glasgow
  3. I’m looking for technical help or recommendations on: __ Trans and Diff oil.

I’ve bought Mobil trans and diff oil last week from MX5 Parts. I randomly went on to check I’d bought the right stuff as it’s the same oil so thought I’d made a mistake.

It was then I noticed the reviews for the gearbox oil and whilst only three all of them are negative.

It’s made me think twice about using the oil and just buying new oil somewhere else.

Has anyone else used this oil in their 1.6 NA?

Thanks

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I saw the review about the diff oil as well, but the review:

says it wasn’t suitable for a limited slip diff, and I’m fairly sure mine is the bog standard one so I got the oil from there anyway.

As to the gearbox, I used the Castrol oil checker and bought what they said:
https://www.castrol.com/en_gb/united-kingdom/home/car-engine-oil-and-fluids/motor-oil-and-fluids-finder.html
(which for my NA 1.8, was Castrol TRANSMAX Manual Transaxle 75W-90).

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Not looked at the specs but if it’s not GL 4 it shouldn’t be in the gear box. Get some 75w 90 Castrol to GL 4 spec, diff same 75w 90 to GL4/5 spec is ok. Some use the Redline MT 90 with good results too.

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Out of interest I tried the Mobil oil checker, for some reason it’s recommending 80w90 GL4/5 for the diff whichever engine type you choose.

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I’ve seen the odd post where members have put the incorrect oil in the gear box and made it worse, probably with looking at the wrong guides online. Always best to check with the OC forums, that’s what I do.

Just bought another daily driver and searched for what engine oil to use, I’m confused to say the least, is it 0w 20, Ow 40 or do I use 5w 30 as recommended by Googling it. Anyways I’m off over to the relevant forums to ask for advice, they have the exact same models so will know👍

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Mx5Parts actually note on the page that 80w90 GL4 is no longer available.

Gearbox Oil, Manual, Fully Synthetic, 1 Ltr, All MX5 Models – MX5 Parts

I think I’ll not bother with the ones I’ve bought £45.00 worth of oil as well.

I’ve used the oil checker you linked and I think I’ll be buying what is recommended.

As one of the reviews says it’s not great MX-5 Parts are stocking an oil which really shouldn’t be used in the car.

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Just checked the mobil oil checker and the oil is fine for the transmission however it’s recommending another type for the diff.

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I used 75w90 redline for the lsd diff and it’s been great, however the mt90 for the gearbox is still a bit notchy 123 when cold, when warm it’s super smooth, probably due to the oil thickness. There is a member on here duratecnc that sells his own blend for the box and has good reviews, tempted to try that next.

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That’s what the Haynes manual is saying. So, I’ll stick with that.

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The redline stuff is quite expensive.

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No NA or NB MX5, from the factory, open, viscous, Torsen T1, Torsen T2, Fuji, needs “LSD oil”.

Some imports might have an aftermarket (typically Kaaz) clutch-type LSD, and that will need a specific oil.

The change quality changes by year, and is hit and miss. Redline might make it feel better, or it might not. Some cars will benefit from having the shift bushes renewed, so won’t.

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This is GL4 only and does the job perfectly for those that need this specifically.
Best to avoid the GL5 compatible ones as “some” have additional chemicals that can effect and wear the soft metals used in gearboxes.
Along with other components the bulk rings wear and hence can cause problems.
Just an opinion.

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That’s what wanted to say but couldn’t remember the technical terms.:smile:

As you say stick to GL 4.

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