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rb25detSpoolin

rb25det with rb20det tranny. speedo wont work need help !!!

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Hi there i have looked a bit everyone and dont know quite whats wrong and how to get my speedo working. My dash cluster is new and 100% working. But still my speedo doesnt move i was told its due to having a rb20det tranny which uses a mechanical speedo while the cars rb25 requires an electrical speedo. I was told that by putting in a rb20e r33 speedo drive would resolve this . Im not too sure on how accurate this is and Id like any tips or ways to resolve the issue. Preferably not too expensive.

 

Im sure many people have done this b4 looking for how to get the speedo working again .

(NOTE : previous owners dropped the 20det gbox in , i was told its a small issue but more i looked into it after buying most mechanics have suggested putting in a rb25det bigbox, i dont see the need as the gbox is tight and strong and I am running no modes all stock factory 100,000kms. engine 60,000km tranny  ) 

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The speedometer determines what type of speedometer drive you need.  You need to describe your speedometer.  If it's a stock speedometer, people could probably figure it out if they knew what kind of car you're working with.

 

Engines don't require speedometers.

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The speedometer determines what type of speedometer drive you need.  You need to describe your speedometer.  If it's a stock speedometer, people could probably figure it out if they knew what kind of car you're working with.

 

Engines don't require speedometers.

 
its a stock rb25det gts25t r33 mspec series 1 1994 if that helps . I realise engine doesnt require speedometre i was meaning the stock rb25 r33 uses a electric speedo drive 
Edited by rb25detSpoolin

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This is an excerpt from page 5 of Chris Rummel's wiring write up

 

Speedo - use Navara D21 Ute mechanical gearbox Pinion Assembley Part No 3270202G17

 

It's what I used and it works, bearing in mind that my diff ratio matched the stock r33 donor.

 

Hope this is helpful.

 

Bill

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From my readings, the smaller rb20 trans uses a slightly different shorter pinion mechanical speedo drive gear. (or at least the rb25de (non-turbo) does and I thought they had the same transmission.

I will re-iterate new-zed's question about wanting to know what speedometer you have. You say your dash cluster is brand new. Does this mean you have aftermarket or newer gauges? It's knowing what the actual speedometer requires to know how to adapt it. If it's new, it may require an electrical signal either from the ECU or an electric speedo sender. If you mean you got new original stock datsun gauges, then it's just like stock and you will just need the mechanical pinion adapter that fits.

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From my readings, the smaller rb20 trans uses a slightly different shorter pinion mechanical speedo drive gear. (or at least the rb25de (non-turbo) does and I thought they had the same transmission.

I will re-iterate new-zed's question about wanting to know what speedometer you have. You say your dash cluster is brand new. Does this mean you have aftermarket or newer gauges? It's knowing what the actual speedometer requires to know how to adapt it. If it's new, it may require an electrical signal either from the ECU or an electric speedo sender. If you mean you got new original stock datsun gauges, then it's just like stock and you will just need the mechanical pinion adapter that fits.

 I mean since it was a auto conversion its a new r33 gts25t manual cluster so its stock. 

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 I mean since it was a auto conversion its a new r33 gts25t manual cluster so its stock. 

In that case, you are right, you probably need an r33 speedo sender from the smaller rb20 trans. I think a lot of people convert the opposite and put in a mechanical speedo sender to use a stock datsun gauge, so maybe put up a WTB for their stock electric senders. Also, if you check the thread on the mechanical speedo drive, I put a link to a good nissan parts site that lets you cross reference different nissan parts. So if you look up the diagram for the speedo sender you need, you can plug in the part number and determine if other nissans use the same one. I would guess that the KA24 trans uses a similar one as I thought the rb20 trans was based off that, but that's just off the top of my head.

 

If you need help finding the part let me know.

Mark

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On 5/29/2014 at 12:20 AM, wrcbonk said:

This is an excerpt from page 5 of Chris Rummel's wiring write up

 

Speedo - use Navara D21 Ute mechanical gearbox Pinion Assembley Part No 3270202G17

 

It's what I used and it works, bearing in mind that my diff ratio matched the stock r33 donor.

 

Hope this is helpful.

 

Bill

It's what you used for your RB20 transmission?

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19 hours ago, jthom5147 said:

OP: you’re running an R33 cluster? The Navarra  speedo gear is for a cable driven speedo gauge / cluster. No it won’t work for an electronic cluster. 

I am running stock 78 280z gauge which is mechanical cable.  I searched around and came across Navarra speed sensor for my rb20det transmission.  The length of the sensor just seemed too long.  It is the right sensor for rb20det transmission with stock 280z gauge?

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