Gearbox/Diff Oil....What's best??

[dragonheart]

Soon to be changing my gearbox and diff oil, was going to order this from mx5parts but after reading the review i am now in 2 minds. What do other owners use?? has anyone used this?? if so what results did you get??

Here is the link to the oil.

www.mx5parts.co.uk/engine-fully-synthetic-mk3-only...

[dragonheart]

Does anyone have an opinion on this??

[Krikkit]

Any reason not to go with the OEM stuff?

[Rum Runner]

Put a tube of molyslip gearbox in the box....massive difference

[MX-5 Lazza]

I use Redline Synthetic in mine. Lovely stuff that improves the gear-change and lasts well.
Should be no need for additives, the gearbox oil should have everything it needs.

[DEKE]

Must say put Moly slip in my gearbox as well, also use STP in my engine oil must be an age thing Lol, have used this over the years in various older cars certainly does more good than harm. LSD on my Eunos so proper LSD diff oil used.
Cheers

[binnerboy]

this thread on mx5nutz is a good place to ask

http://www.mx5nutz.com/forum/index.php?showtopic=1...

here is what Opie Oils said when I asked for a recommendation for geabox and diff oil for a 1994 mk1 1.8 eunos

"You need a 75w-90 for the gearbox and diff

If you want to go for the best, the Millers CRX 75w-90 NT, Gulf Competition, Motul Gear 300, Red Line MT90 and Millers TRX are ideal for the gearbox. The Castrol Universal/Universal Plus/Syntrans Multivehicle, Motul Motylgear and Fuchs Gear Syn are all decent alternatives. The Fuchs Syn 5, Motul Gear 300LS, Millers CRX NT LS, Gulf Competition LS and Red Line GL5 are ideal for the diff."

[dragonheart]

Would the same oils be used for the 5 speed?

[Richyvrlimited]

DEKE said:

. LSD on my Eunos so proper LSD diff oil used.
Cheers

The LSD you have is either a Torsen, which works via gearing, or a Viscous unit, which is sealed.

Neither of these differentials need proper LSD oils, those are meant for LSD's with clutch packs so need friction modifiers to allow the wet clutch packs to do their job.

[MX-5 Lazza]

In mine I use Redline MT90 (which is a 75w/90 formulated for manual gearboxes) in the gearbox and 75w/90 (which is what its called, obviously its the same weight as MT90 but without friction modifiers).
It comes in quarts so I buy 2 quarts of each. One and a bit of the 75w/90 goes in the dif and he full 2 quarts of MT90 goes in the gearbox. I then use the remaining 75w/90 to top off the gearbox.
6 speed doesn't have turret oil but 5 speed does. You can use any oil you like in there, gearbox oil, engine oil, extra virgin olive oil...

A handy tip - with the 6 speed the turret is lubricated by the main gearbox oil. This means you can refill the gearbox by pouring the new oil in via the turret. You can't do that with the 5 speed with which you have to find a way to feed the oil in via the oil level hole.

[g40steve]

He has a mk3 so I would advise not trying to fill through the turret.
I got flamed for posting links to nu?z but it will answer your questions.

[MX-5 Lazza]

LOL I always forget about Mk3s!

[Vin]

oils is a large debate but my spares man said to me commer will do the job. changed the gearbox oil and I could not change it from cold. Drained it and replaced with a brand name and it then resumed to normal operation. I would suggest any oil apart from commer or a cheap make not known.

[MX-5 Lazza]

Comma

I suspect it was either the wrong grade of oil or an oil not formulated for synchromesh manual gearboxes. There is no reason why Comma oil shouldn't work fine, they are not a small/unknown company. They make my coolant of choice - Comma Xtreme Gren.

[DEKE]

Hi All
Reading these posts will using the LSD oil harm the diff? Been in since around March doesn't seem to be any issues yet and have done a small test/track day. Thanks

[MX-5 Lazza]

DEKE said:

Hi All
Reading these posts will using the LSD oil harm the diff? Been in since around March doesn't seem to be any issues yet and have done a small test/track day. Thanks

Probably not. It's a mechanical dif so there is no need for any kind of friction modifiers. It won't do anything to help it but I can't see that it would hurt it either. Ask on Opie Oils.