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dave_hl

Speedo pinion gear (blue and white)

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a few things i need to figure out regarding speedo gears.

- i have a 1980 ZX which was auto

- it was changed to manual in 1988 with a 5 speed geabox (not sure what yr gearbox is)

- i pulled the speedo pinion gear out of it and its a white 19 tooth one.

- i orderd a new speedo gear from nissan and after telling them it was from a 5 speed 280zx they got it in and its a blue 18 tooth gear.

 

so basically i dont know if they're idiots because maybe the blue gear is for a 4 speed or something or whether the 5 speed has both types depending on year, which they didn't ask me for, hence i was under the impression that there was only 1 type of speedo gear for the 5 speed.

The other thing which screws it up even more is that i have bigger wheels which were put on about 18 months ago so that would make the speedo reading even more inaccurate as well.

i hope this makes sense and someone can assist me. i think i am able to return and get credit as i havent opened yet, except that they had to order it in from some other nissan parts place.

cheers.

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I am sure that someone here can explain this perfectly..

 

From my knowledge there is a few different gearboxes for the 280zx. And yes there is 2 or 3 different gears available, i have no idea what they all mean, but do remember reading an article about it a few years ago, i think it made mention of white/blue and red gears, and possibly a yellow one? not sure.

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The speedo gears have nothing to do with the gearbox from memory, other than the body type - the actual cog is tied to your diff ratio. Which will be why you were given a different gear, as your car was originally auto, and therefore should have a different diff ratio to a manual car, unless that too has been converted. Nissan would have assumed it was factory manual, and given you the speedo gear for that diff, but your car most likely still has the auto diff.

 

Have a look at this link http://www.geocities.com/zgarage2001/, the section headed 'Fourth' talks about the different speedo drive cogs. You may be able to correct your speedo by using a different cog to counter the effect of the tyres.

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oh ok makes sense, except i thought the speedo connects into the rear of the gearbox, so if the gearbox was swapped with a manual one, all the speedo conenctions would have changed as well. (ie it would have the 5sp speedo gear)

ill give nissan a buzz tomorrow and see if i can just swap it over for a white 19 toothed one because if i was going to correct the wheel size difference then i would need a cog with more teeth anyway so it spins the cable slower. I think the white one like i had should do the job good though coz i drove it home from from newcastle on the hume and didn't get any speeding fines even though my speedo said i was sitting on 110km/h. so it cant be too out.

And yeah i remember reading that page on the speedo gears a while ago and couldn't remember where i saw it. thanks for the help.

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Probably means that whoever swapped the gearbox in knew how it worked, or took a guess that the drive gear needed to be swapped.

 

Either way, glad to be of assistance.

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well i finally picked up my white 19 toothed speedo pinion gear today but am having a couple of problems installing it.

firstly i cannot open the gearbox refiller plug on the side, it is as tight as tight can be. ive tried getting under there with both hands pullling and pulling as hard as i can with a spanner putting all my 105kg of body weight into it. is it a reverse thread or something?

and also i slotted the new gear into its sheeth and plopped it into the speedo hole and then tried turning the pinion and it turned freely. is this normal? i would have thought it could only turn if the drive train was turning. It did this with the broken one, and i thought it did do it because it was the broken teeth on the pinion, i just hope it isn't something else, otherwise.... buggerrrr.

thanks guys.

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The gearbox refill plug should not be a reverse thread. It might need some gentle persuasion in the form of a hammer on the spanner. If that doesn't work, put a bar over the end of the spanner for extra leverage.

If that doesn't work, I have heard of heating the plug and around it to break the bond.

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ok heres where im at.

put the new speedo pinion gear in... managed to undo the gearbox filler plug and topped up the gearbox then went for a drive to see that the speedo still doesn't work. ARGFHGHHGHGHGHG.

so annoying. even with the new speedo gear it would still just spin freely in its sheeth, ive asked this a couple of times, but would that mean more severe problems in the gearbox where the speedo gear connects to the drive train?

what i mgiht try is going for a drive with my arm in the dash feeling if the cable is spinning up at the dash end of the car, and get someone to do the gears.

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