I am having the same issue on my imported 2003 Mk2.5 1.8 SVT 6-speed. I thought this will happen only during the winter but it’s pretty much similar during warm days too. I think a few times that the car was exposed to the sun the start was quite smooth, but I don’t really think that air temperature can affect the inside parts.
To be honest, I am a bit worried about it, I really think that something is about to break down there. I am trying to not start immediately and wait for 5 minutes or so. I will try the 1st - Neutral - 2nd which makes sense.
It is my first car and is my everyday car, I like it very much, doing some compromises though and I don’t have a problem with the notchiness but, as I said earlier I hope it will not cause any problem in the future.
By the way, I wanted to create a topic for this issue so thank you guys for posting your experiences with the older car as well.
Hi Bill. Gearbox oil needs to warm up before it becomes fully efficient, hence it’s frequently the case that a notchy change with a cold engine / gearbox will improve when operating temperature’s reached.
The worst car I’ve owned in this regard was a 1993 Vauxhall Corsa, bought new & from day one it was very difficult to get from 1st to 2nd when cold, without crunching the gears. I owned that car for 9 years & the problem never got any worse. After a mile or so, it was fine.
On the other hand, gear selection difficulty can be a symptom of clutch or gearbox issues, e.g. if the clutch isn’t fully disengaging which could be caused by a clutch (or hydraulic if it’s hydraulically operated like the Mk3) fault, or the need for clutch adjustment, or a mat between the pedal & the floor or the driver not putting the pedal fully down before shifting gear. In the case of the gearbox, it could be worn synchromesh, or low oil, or incorrectly graded oil, or simply the need for a gearbox oil change.
If it’s worrying you, my advice would be to ask a reputable garage to check it out - if there are issues then at least you’ll know about them; if there are no issues then it should put your mind at rest.
The NC’s gear linkage turret isn’t fed from below so well worth checking. Both of the NCs I’ve owned had zero oil at about 50,000 miles and adding the recommended 230ml did make a difference; not perfect from 1st to 2nd when cold, but better.
I have driven a NC 3.5 – 6 speed for 5 years, and the gearbox oil has been changed to the recommended Castrol Syntrans variant. I still get a notchy gearchange when cold, but have learned to live with it. With some past experience of testing oil viscosity, I have reached a few conclusions over the years.
When cold, the oil acts like glue, sticking the synchro cones and dogs together, causing a balky change. This effect disappears as the oil becomes more fluid as it warms up. I think the threshold temperature is 25-30C judging by an easier change on a hot summer morning. The gearbox oil temperature will be at ambient on a cold start and is largely independent of engine temperature, but generates its own heat by the processes of power transmission. It seems to take 25-30 mins of normal driving on a cold morning to heat the oil up to a comfortable working temperature.
I believe the underlying cause is due to Mazda squeezing a 6 speed box into a tight volume. This puts high contact pressures on small meshing surfaces – hence the need for sticky oil – and reduces clearances and dwell times during gear changes so there is more spin drag to overcome.
Like most, I take it easy through the box when cold but, paradoxically, have found it possible to get a slick change at high revs on the odd occasion. I put this down to high shear forces in the oil film in such circumstances.
I also had a problem with an 1989 323 4x4, never did get to sort the problem out despite numerous oil changes and different additives. l learnt to live with it but not good on a high performance car, my 2009 mile 3.5 is the same but does improve after several gear changes as the oil warms up. Never really had the same problem with other cars so perhaps it is Mazda engineering tolerances. It is still a great fun car so I put up with the gearbox, it is not really a good thing with a performance car but we still love them!.
Not specific to MX-5’s, but I can recall two experiences of cars with baulky/difficult gear changing in my motoring life of about 47 years. Both were caused by clutch drag.
I never thought the clutch was dragging on my NC, but since I’ve adjusted the pedal bite point up towards the higher end of the Mazda specified range it has felt much better. Now it behaves as a clutch should, something not to have to worry about.
My 2010 Mk 3.5 with just about 41k on the clock is notchy too. Interestingly, I find it harder to match revs and biting point when pulling away when it’s cold too, despite 40+ years driving experience. i still wouldn’t swap it for anything else though. SWMBO has a brand new Mazda 6 and while The gear change is silky smooth in all conditions, I’m not a fan of having my left foot up by my neck every time I change.