NC Sport, gearbox very stiff in heavy stop start traffic

Had an issue recently, i was in heavy stop start motorway traffic and after a little bit the gearbox became VERY stiff and it was alarmingly hard to select any gear, however, once the traffic cleared and i was up to speed again it was fine! Has happened again since in heavy traffic.

Have had the gearbox oil changed recently, am i right in thinking this is a clutch issue?

07 2.0 Nc Sport

Any help, much appreciated

Have you checked the clutch pedal freeplay? on some NC the pedal can move a lot before the clutch master cylinder rod is engaged. You can check it with a torch if you get yourself upside down in the footwell. Easy fix and makes the gearbox feel so much nicer.

Lots of small things can be done to improve the gear change. It’s usually from 1st to 2nd owners complain of a stiff change, when cold in particular. Oil change, one member has a magic formula you can try, never done myself.
Adjust the bite point at the pedal, I’ve done this with improved changes, change and bleed the fluid on the clutch side. Also there’s a plate you can change on the top of the shifter, it gets worn, I’ve changed mine and it has made a small difference.
Learn how to change gear a little different 1st to 2nd can be notchy until warmed up.

Anyways until someone else tests drives your car to compare to another it’s hard to know whether the clutch is ok or not good (worn) so but try the above mentioned first.:+1:

You don’t mention how many miles on that clutch?

Thanks, I haven’t, i will check this out

Car is on 76000, no idea if it’s been replaced in the past.

The bite point is quite low to be honest and i do practically have to put the clutch to the floor to change gear.

I’ll check the easy/free things first that you and carl suggested, cheers!

When I had my gearbox oil changed it took a while for the gearbox to get back to normal.
I struggled to get into any gear once I had stopped the vehicle and went in to neutral.
Took about 2 weeks and after that it was back to being a normal gearbox, seemed strange.

Now I will go from 1st to 3rd because 1st to 2nd is not smooth until the box is warm and will keep in lower gears for longer so the oil warms up quicker.

I reckon the pedal adjustment will improve it no end…

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The slave cylinder is strapped to the gearbox. When you sit in traffic, it gets much hotter than “normal” as do most things under the bonnet and it can result in things becoming less free. And, since the clutch is rarely, if ever bled, then the fluid can aerate and therefore not giving the clutch full travel.

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Agreed!

When I bought my NC at 17,000 miles and six years old the “brake fluid” had been done on the service intervals. The clutch fluid shares the brake reservoir, so should be bled at the same time!

BUT the clutch was on the floor, (a buying haggle point) and my first thought was to bleed it. What came out was pitch black and sticky. Eventually when it ran clear, obviously never bled before with loads of black sludge, the clutch was a lot better.

A few years later I finally adjusted the master cylinder bite point with the aid of a bath stool to support my hips beside the car.

It took two goes a couple of months apart before I was happy. Original post updated with this in mind and a picture.

Now at thirteen years old it is simply excellent, and more recent scheduled services did bleed the clutch slave too.

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Had the same problem on my car when I first had it (Miyako NC 48k miles).

Adjusted clutch peddle to give minimal clearance …
it must have some clearance!!!

Bled the clutch.

Sorted.

Roy

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I had exactly the same problem on my 2007 Sport and fully bleeding the clutch sorted it… after trying all the other suggestions.

However, the other suggestions did improve other characteristics of the gearbox-clutch-pedal behaviour but bleeding fixed the heat induced lack of full clutch disengagement.

John

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I’ve had this issue before.

If it’s happening when in stop/start traffic, it’s indicative of the clutch fluid possibly getting too hot/starting to boil. This shouldn’t happen unless the fluid is very old and has water content (remember that brake fluid is hydroscopic).

If this is happening then the fluid will change in density enough that the bite point will change, resulting in the symptoms you’re describing.

A very thorough bleed and fluid change resolved it for me, so I would start there.

As for your dissatisfaction with rhe biting point… Same here… Wind the pushrod on the master cylinder out by 1/2 a turn, it makes the world of difference.

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I’m booked in at Mazda for a clutch bleed, quoted £70 for it. I’m not sure if they change the fluid too, i should ask. I will definitely have a go at doing that clutch adjustment as well

Cheers everyone for all the help!

Coming up on 1 year of mx5 ownership this year!

As long as you don’t mind squeezing your head down and under the steering wheel adjusting the clearance to minimal is easy with two open ended spanners, 14mm and a 12mm rings a bell but don’t rely on these spanner sizes.

Good luck and keep us all informed please.

Roy

Yep, can’t bleed bleed it without replacing it with clean fluid = it is getting changed.

@Kit_Car_Roy, close, 10 and 12mm :wink:

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Late update!

Got the clutch fluid changed and it has made a noticeable difference, feels smoother, it’s a lot smoother than it was when cold too.

I still plan on doing the clutch pedal adjustment as it still doesn’t feel quite right, can change smoothly at high rpm but it’s hard to get a smooth judder free change at low rpm.

But physically getting the gear in is now much easier thanks to the clutch fluid replacement and gearbox oil change i had done not long ago. The gearbox has been my main disappointment with this car, particularly because i heard such good things about it, hopefully with the pedal adjustment the gearbox will be as good as it can possibly be without getting a new one!

Thanks for all the help with this, the power of the mx5 community is impressive!

Some new pics of my car. I replaced my shabby oem sport 17" alloys in the summer with some black powdercoated oem 16"s that i got off ebay for a fantastic price, very happy with the look, i don’t know how this is possible but in my eyes the arch gap looks smaller with 16s on!


Looking good :+1: the black 16’s suite that colour car with the roof down, definitely worth the investment in an uncomfortable 30 minutes upside down in the footwell, as I mentioned in a previous post it completely transformed my mk3’s gearchange

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