Which gearbox oil to use for a series 2 nb

[Aussie Stig]

Again GL-5 is fine as long as it has a military spec attached.

MX5 gearboxes are not the only Mazda gearboxes with brass synchos built in the 90s and early 00s. All this has been tried and tested and proven before.

I am sure the aisen 6spd was also used in RX-7 and Lexus. I wonder what they are using.

[Aussie Stig]

I would have thought the gearbox oil would never wear out as it is a sealed system but apparently it should be changed about every five years/75K

Looks like something I should be scheduling as I am sure it has never been changed in 10years.

[manga_blue]

A Castrol ( BP) or a Shell are actually oil co's and can produce a variety of quality oils with massive resources backing them.

The big brands, Mobil, Shell and BP (Castrol) have quality oil manufacturing plants in Europe and Nth America. Unfortunately oils branded Mobil, Shell or Castrol made in those plants are not sold here in the mainstream channels. The oils they do sell here are mostly made under contract by plants in Sth Asia and their quality is not the same. If you do want to use these brands then find a niche importer who advertises Shell USA or German Castrol or Mobil USA. There are a few on ebay AU but they're not cheap, in fact they're priced with the next level up performance brands like Redline, Royal Purple and Amsoil.

I'd go with the Nulon recommendation simply on the basis that the people recommending it here actually know their stuff and have used what they recommend. Personally I've used Redline MT90 in my 5 speed on and off for years without a problem and I've found everything else that I tried was less good, i.e. either crunchy, baulky, notchy or noisy.

Beware Castrol Syntrans, my car was pretty much undriveable with it because of baulking. I had to drain it out after a week.

[project.r.racing]

Again GL-5 is fine as long as it has a military spec attached.

MX5 gearboxes are not the only Mazda gearboxes with brass synchos built in the 90s and early 00s. All this has been tried and tested and proven before.

I am sure the aisen 6spd was also used in RX-7 and Lexus. I wonder what they are using.

This is what I use:-

http://www.penriteoil.com.au/products.p ... oducts=376

for my 323 with transaxle gearbox and hypoid clutch plate lsd. and have so for 100,000km. it's a GL-5 75-90.

oem spec normally is GL-4 75-90 same as mx5.

[project.r.racing]

I would have thought the gearbox oil would never wear out as it is a sealed system but apparently it should be changed about every five years/75K

Looks like something I should be scheduling as I am sure it has never been changed in 10years.

depends on usage. but 5 yrs 100,000km would be normal for a manual box. more fequent if towing or zoom-zoom-ing alot.

[manga_blue]

Mazda's owners manual for the NA lists gear oil replacement at 60,000kms or 4 yrs, whichever comes first. Same for the diff.

Mazda's General Information guide lists 96,000kms or 4 years for the NB 6 speed. Same for the diff.

[JBT]

NC Owners Manual shows change diff oil at 80,000km and 6 speed manual transmission oil at 100,000km. Only specifies GL-4 for the transmission.

[mx5002]

Sorry to hijack
But while on the topic, how much oil does the gearbox hold?

[93_Clubman]

I've just had a look in the NB8B service manual and it says this:

Specified oil:
Grade: API service GL-4 or GL-5
Viscosity: SAE 75W-90 (All season) or SAE 80W-90 (Above 10 degrees C {50 degrees F})
Capacity (approximate quantity): 1.70 - 1.80L {1.79 - 1.90 US qt, 1.49 - 1.58 Imp qt}

viewtopic.php?f=29&t=50062&p=634163&hilit=NB8B+gearbox+capacity#p634163

[hks_kansei]

Sorry to hijack
But while on the topic, how much oil does the gearbox hold?

Gearbox ~2l
Diff ~1l (for the 1.8 diff)


But, there's no need for any proper measuring, just fill it until the oil starts to dribble out of the fill hole. (that's why the fill hole is on the side, not the top)
Diff is the same.

[manga_blue]

If you buy one of the american market ones then you should have a teaspoon or two left over from 2 quarts.

[slimx]

I know this topics pretty much over but just in case someone comes along and reads it again. Moral of the story

Get the REDLINE , 2 Quarts does you fine!!!
http://www.skreem.com.au/MTL-QUART

[hks_kansei]

I know this topics pretty much over but just in case someone comes along and reads it again. Moral of the story

Get the REDLINE , 2 Quarts does you fine!!!
http://www.skreem.com.au/MTL-QUART

viewforum.php?f=82

[tescoking]

Two options.

Option one:
Go to AutoPro and get Nulon Full Synthetic 75W-90 Performance Smooth Shift Manual Gearbox and Transaxle Oil.

Nulon Full Synthetic 75W-90 Performance Smooth Shift Manual Gearbox and Transaxle Oil

http://www.nulon.com.au/products/Gear_a ... saxle_Oil/

I believed this is the only shop that have this in stock.

And you should be able to get G70 in any auto shop.

Nulon G70

http://www.nulon.com.au/products/Specia ... Treatment/

Mix G70 into the gearbox oil before filling into the gearbox oil.

Option two:
Like other people said, get redline 75w-90. I have never use this before, and I believe you have to purchase it online since this is U.S. product - ebay is your friend.

http://www.ebay.com.au/itm/Redline-oil- ... 2a2f3beaa0

5lite will be more than enough.

And at the end of the day, the most important thing is a regular oil change - Every 3 months or 5000KMs.

[nd55]

Just to clarify, GL-5 oils which do not have sulfur compounds are OK to use in manual transmissions.

It's the sulfur which compromises the copper metal in the syncro rings.

Or you could just use GL-4 oil in the transmission, as there are plenty to choose from.