mx5cartalk.com

Probably the wrong product for the MX-5, the recommended Redline oil is MT90. That said, I used it in my NA and didn't like it at all. Did you check Miata.net forums for recommendations before you used that particular oil?

I'm finding the hotter it gets the better the gear changes become

Changed mine about two weeks ago having about 15-20,000 kms on the oil and could see no signs of clumping etc , only a slight change of colour to the new oil.

New oil would have only seen 10km's or less thus far...

i used it in my car and it seemed fine... my brother at the same time put it into his soarer and it made it so his gearbox no longer ground when going into 3rd no idea how but i was in the car before and after and it did stop it...

i recently changed my G'box oil to penrite 10/10ths and when draining didnt notice anything glugy about it.. and ive tracked the car with that oil about 3 or 4 times now..
HOWEVER i must admit i have started to notice a bit of a grind when going into 5th now!?!
so maybe it has started to kill my syncros

I once used the Redline blue in my gearbox and it was very thin and the gearbox was a little noisy. One stinking hot day on the freeway, it started to get notchy and eventually jammed in 5th and it took both hands to get it back out, and after that I couldn't get it back into 5th.

Swapped over to a thicker oil immediately (just a cheapy Valvoline Duragear or something) and it shifted smooth again.

Dunno if maybe it was just an issue with my gearbox but since then I've stuck to the thicker 75/90W oils as recommended in the handbook and never had a problem.

Not sure where some of these ideas come from... Redline Aust site recommends MTL Lightweight Shockproof oil for all MX5 gearboxes. It is a fully synthetic based oil that cannot possibly harm your gearbox - it is a lubricant not an abrasive! The difference between one oil and another under operating conditions is in how well it does the job - I have not heard anyone say that MTL LS failed to do the job, I've heard some say it was no better than whatever they were using before, and I've heard a lot of people say it is fantastic (me included). If you were using a non-recommended oil from Redline (like MTL90) then I could see potential problems occuring (it would be too thick). Go here to read all the tech data on Redline Shockproof oils: http://www.redlineoil.com.au/Uploads/Downloads/SPGO%20TR%2002_03.pdf

As far as short life span is concerned the Redline website claims that gearbox oil change intervals on an MX5 can be extended by up to four times by using MTL LS. And note that the viscosity rating well exceeds the 75W90 of ordinary gear oil too.

I've been using MT90 (and not MTL) for years without any dramas.

IMHO shockproof is used by a lot of drivers (especially WRX drivers) rather than fixing an issue in their gear box. I think some may find it easier to blame the oil rather than their driving style.

I’d want more conclusive evidence than one person’s opinion on a forum, especially considering I don’t know that persons credibility, driving style, car and any underlying motivation to push/put down particular brands.

I wouldn’t be using their “shockproof” oil in a standard MX-5 gear box.

I know a bloke that I'm pretty sure used to use Redline shockproof in his WRX gearbox. Ended up crashing the car and when the gearbox was sold it was dismantled before being used by the new owner and after 100,000km's it looked like new. He also used to Heel n Toe all downshifts and double clutch upshifts which would reduce synchro loading. But the problem seems to be bearing and gear wear which they didn't notice at all.

Here's an interesting read on what a Mazda engineer recommends.

http://forum.miata.net/vb/showthread.php?t=203665

Ok... I still have no idea what to get for my NA8

No need for hesitation on this question - if you are happy with the way your gearbox is working now stick with Castrol 75W90 Gearoil.

If, like me, you are troubled by the notchiness of the shift mechanism then give the Redline a try, or one of the other 'super' synthetic gearoils like Mobil 1 or Amsoil etc.

There is no point in spending money for no reason. If there is nothing wrong to start with, how would you notice an improvement? I repeat what I have said earlier - in my case the improvement was remarkable, so I'm more than happy. I may have seen a similar improvement by rebuilding the box with new bearings and syncros, but Redline is a lot cheaper...

I had assumed with the name \"drifter\" that you would have been giving the NB a bit of stick.

As BD said, if you are a normal day to day driver, stick with the recommended oil weight changing the gearbox / diff oil at the recommended intervals. For the NC that’s 100,000klms for the gearbox and 80,000 for the diff.

If you do a few track days then you should consider upgrading the oil or at the very least change it on a regular basis, ie 20,000klms.

You may need an \"accurate\" wheel alignment.

JBT wrote:You may need an "accurate" wheel alignment.

What he said. Get a good custom alignment by a reputable shop and dial in your wants and needs. Very big difference - mine's set up with pretty agressive front end bite - it doesn't understeer and has an inherant want to slide the arse a bit.

You can neutralise this, just go to a decent shop and havea chat.

Cheers - Mike

Adam_NAclubman wrote:Ok... I still have no idea what to get for my NA8

Castrol - the one recommended for 5 speed Mazda gearboxes.