gearbox is jamming - nissan micra 1.2 '89

Is your clutch disengaging completely?

or to ask the same question a completely different way, if you give it a very little gas while experiencing this problem, does it change the behavior of the shifter any?

nate

Hello Nate and all,

Thanks for the rêply. No, I'm depressing the clutch normally, but I haven't tried to give a little gas during gear shift. As it only happens EXITING 3rd gear, would it be a likely explanation ?

Thanks again,

Carl

It's one possible explanation; I have found that if the gears are loaded even slightly that it will be hard to pull the shifter out of gear (as well as you may notice an issue trying to shift in once your synchros start to wear.)

nate

Hello again,

I can try to check clutch operation, maybe it needs to be adjusted. But none of the other gears suffer.

I remember having reverse gear grinding almost every time I shift to reverse impatiently, but it wouldn't affect 3rd gear behaviour, would it ?

Rgds,

carl

Usual rule of thumb for only one gear affected and no nasty noises is either broken/worn/damaged gear linkage or cable, or a broken engine mount.

Chris

Hello Chris,

Do you mean gear linkage inside the gearbox ? I checked the outside and found everything working fine, no excess play between linkages. But would it produce problems exiting gear ?

Thanks,

carl

External to the gearbox.

Lack of play is good, what about adjustment? You are probably going to need a manual for that.

Have you looked for a broken engine mount? Try rocking the engine vigourously.

Although it's possible that it's an internal gearbox problem, from your description it sound much more likely to be external IMHO.

You only posted a short time ago, so perhaps someone with more specific Micra knowledge will be along later.

Chris

Hello Chris,

I suspect 5th gear operation would be unaffected by 3rd gear linkage adjustment problems ? Or would it suffer to the same degree as this 3rd gear ? I didn't shift to 5th gear lately ...

I hope indeed someone experienced nissan mechanic shows up. Adjustments to the linkage would require a lot of time I gather, since the problem only shows up under load, as Nate pointed out.

cheers, Carl

Hello again,

I forgot to say, that the car sometimes is moving slightly forward - this morning it moved backwards though - when the engine is running stationary. Yet it does not do this when at working temperature, then it just sits, clutch depressed and put into a gear. Just additional information, but it seems not too revealing.

Regards,

Carl

That makes almost no sense at all but what I *think* you're saying is that with the engine idling, the car will creep forward when in gear but with the clutch depressed. If that's what you meant to say, then clearly the clutch is dragging which would explain your gear engagement problem.

If it's creeping forward with the gearbox in neutral then I've no idea what's wrong.

Tim

(Top posting corrected)

Carl, when you reply to a post please do so *under* what is already there. Top-posting is generally considered a bad thing on usenet because it makes it so hard to follow a thread.

The information you have posted appears to contradict itself. To see whether you have a problem with the clutch dragging, when you select first gear and pull away how far does the clutch pedal move before the car starts? If it only moves a small amount from the floor, your problem may be with the clutch, or the adjustment of whatever operates it.

I discounted this as a likely cause of your problem because clutch drag should make changing difficult between all the gears, and you specifically said the problem was only with third gear.

Chris

Hi Chris and all,

Thanks for the advice on top posting. I only sinned a couple of times in ths thread...

As for my gear problem, I got some non-usenet advice, and there are several other explanations. There could be jamming in the gearshift levers in the gearbox, that is, they are safed by some pins in the box, making it impossible to shift in two gears at the time. These could get worn and cause problems. Otherwise there could be explanations in the wear of the external gearshift mechanisms. It is hard to find any indication of the latter.

I analysed a bit further while driving. When the vehicle is not moving, there is no problem whatsoever to get out of 3rd gear. It is only getting out of the 3rd gear when the car is moving that is causing trouble. Can this help with the troubleshooting ?

Regards and thanks again,

Carl

Hi, I have had exactly the same problem with my Micra. However it has now got to the point that it is jammed in neutral.

I will be seeing a gearbox specialist friend of mine sometime this week. I will report back to this group and let you know what he finds.

I hope for both of us that it is not too expensive to fix!

Regards, Pantagoon

Hi again,

After a bit of a web search I have found that this is a very common Micra problem and it is caused by a cracked 3/4 syncro hub.

Pantagoon

Hi Pantagoon,

and thanks for the information. My worst fears confirmed ... At least if you are also having no problems with getting INTO 3rd gear ?

I am looking forward for your next posting !

Thanks again

carl

Hi Carl,

Initially it was only a problem getting out of third - the 3/4 synchro hub eases that transition. Eventually though, it started to be a problem to get out of any gear. I should have had the box looked at before it got to that point! I think the hub has broken completely and the loose bits are now jamming everything up.

Regards, Alan

Hi Alan,

Thanks for your comment. Since a while now, I am just using 1st, 2nd and 4th gear, except when I know I will have to stop again after a short distance, then I still use 3rd gear. As you said, there is no problem when the car has stopped moving, to shift out of 3rd.

I hope this will be enough to avoid problems. You said you will contact a gearbox specialist. Let me know please, what the outcome is.

What exactly does '"3/4 synchro hub is cracked mean" ? Is it broken into pieces ? I don't know what exactly the synchro hub is, and where this damage will be located..

Thanks again,

Carl

Hello Tim,

What you're saying is what I meant. Thanks. The clutch is behaving normally though, I just had some advice saying it could be a serious synchro problem in the gearbox itself.

Cheers,

Carl

Hi,

The synchro hub is a specially shaped toothed ring that fits onto the main drive shaft in the gearbox. 3/4 means that it is the ring used when moving from 3rd to 4th gear. At the moment it sounds as if yours is just cracked and not broken into pieces as mine is.

I must say that I am no expert when it comes to these things - the information I am getting is from my trusty Haynes Service Manual.

If you want to fix the problem yourself, it will mean stripping the box completely and replacing the ring - something I wouldn't contemplate doing myself. My friendly expert is coming for the car on Wednesday morning. I'll ask him some more questions. It may be quicker and cheaper to get a secondhand box from a breakers and fit it. This would be much easier than stripping the box.

Regards, Alan