NC Notchy gearbox particularly cold

[Mr Morlock]

there are lots of posts on this subject including NC and earlier models. The search feature will assist. Many will suggest using Redline oil. I think that the truth is that the gear change should be taken carefully without rushing the process whilst the gear oil is warming up. The old saying that "they are meant to be like that" does have some relevance and it at least reminds a driver to show some respect for a manual change whilst it warms up.

[Penguin]

We have an 06 NC with the 6 speed box and for the first couple of shifts into 2nd and to a lesser extent 3rd, the box is really tight and feels quite notchy. The car has only done 50,000km.

Once it is fully warm it is much better but 2nd still doesnt feel great and you certainly cant 'FAST SHIFT' from 1st to 2nd.

Ditto with mine, that has only $20K. Seems to be getting better, but I have always taken it gently with 1st and 2nd when cold. No trouble with higher gears. Thought it may be endemic rather than just mine. Any damage to the boys using their cars on track days?

The gearbox still feels fine when it warms up so I am hopeful that no damage is done if I am kind when it is cold.

I am also keen to hear of others experiences.

[SuperMazdaKart]

fast shifting?

is that the same as flat shifting?

[Charlie Brown]

Sounds like the typical "problem" that most NC owners have.
There's been miles of talk about this on Miata.net where most of the Yanks live in areas that are a lot colder than us.

Mine did it/does it. I changed the G/B oil at 5,000 kilometres to a full synthetic (Penrite 10/10ths). It made a slight difference but nothing great.

You just get used to the first few changes being slow and hard.

If you can't select 3rd then you have a bent selector fork, which is a know problem with some early boxes. One member of our Club had it (Blue Bludger) and it was fixed under warranty.

[zombie]

The new (2009) NC now has carbon coated synchros on the first 4 gears, for smoother shifting. I'm guessing at least partly in response to this oft-reported "problem"

Larger synchros in 3rd-4th too, although I've not seen any complaints about those gears in the current NC

[JBT]

1st to 2nd or 3rd to 2nd when stone motherless cold can be a bit sticky sometimes, but easily fixed with a double de-clutch. Shifts on mine are then become rifle bolt slick after about 1 or 2 km.

[mx5racing]

Generally the internals of the boxes are very good. That said there are nylon selector "washers" for all the gears that we have broken in the race cars. The 3rd/4th one is particularly vunerable as has been the failure point for 2 of ours. We also broke one selector. There is an adjusment available for 3rd/4th which limits the throw and takes the pressure off the bush. We have now replaced all our bushes with alloy ones, done the throw adjusment and have not had any other issues with the selectors. Mis-shifts and vague shifts have also been eliminated. We now do this mod for all the boxes prior to the car hitting the track.

I have only heard of one nylon bush failure in a road car.

If you are having issues with the box whilst under warranty report it to your Mazda dealer and get a written report of their determination when you collect the car. If it is a pre-existing problem/issue then it stands a better chance of getting covered even if the warranty has expired. If you just ge it back with a verbal "we couldn't fault it" then you dont have a leg to stand on. Most dealers are suddenly able to find these issues when you ask for a written report as it can come back to haunt them in the future.......

[russs]

If you are near Penfold Burwood and interested their ability to service anything more complex than a wheelbarrow, email me. Maybe we can compare gearboxes.
My NC was serviced there, but if I describe my clutch/gearshift experience with them online, I may publicly embarass them... a lot.
I took them the problem several times, eventually they promised to get Mazda's area rep to look at it... I think that was late 2007... I'm still waiting. Problem IS now solved, but not by Penfolds service department. Thanks Tony Petropoulos.

[russs]

You have a message.
Russ

[CoffeeBoss]

If you just ge it back with a verbal "we couldn't fault it" then you dont have a leg to stand on. Most dealers are suddenly able to find these issues when you ask for a written report as it can come back to haunt them in the future.......

This is very good advice!

Just reviving an old thread.
My gearbox is notchier and reluctant when cold, but this is no different to most other Japanese 6 speed cars I have dríven, including my last one whose gearbox was made by the same manufacturer i believe (AISIN).

However i have noticed some of the vagueness creeping in when going from 2nd - 3rd. 4th - 3rd is fine since it's all lined up, but 2nd - 3rd doesn't have that 'telepathy' of movement you get with the NA and NB gearboxes and there is often a slight 'meshing' to be felt as it goes through the gate unless revs are above 3000rpm and perfectly matched (i'm still not that good).

I shall mention it at next service, but i'm also interested to hear if anyone is using non-standard gearbox oil. Phil uses Penrite, Chris from memory uses Elf, any other suggestions?

It should be noted that this is a fairly minor thing - the AISIN gearbox in my Lexus was never as good as this gearbox, and those gearboxes are known for their inability to get a smooth 1st-2nd shift.

Matt

[JBT]

How many km have you run up now?

[CoffeeBoss]

How many km have you run up now?

Just passed 53'000kms last week.

[JBT]

Gee, you've been getting around. I've only got half that distance up. So far, so good though. The extra good is that it has become somewhat less notchy in the 1-2 or 3-2 shift when stone cold. Otherwise the changes are still slick at this stage.