Jump to content
SAU Community
  • Welcome to SAU Community

    Welcome to SAU Community, like most online communities you must register to view or post in our community, but don't worry this is a simple free process that requires minimal information for you to signup. Be apart of SAU Community by signing in or creating an account.

    • Start new topics and reply to others
    • Subscribe to topics and forums to get email updates
    • Get your own profile page, build reputation and make new friends
    • Send personal messages to other members.
    • See fewer ads!

    Consider joining our newsletter for the latest content updates

    Click here to register

RB25DE gearbox speed sensor

Recommended Posts

Hey Guys,

I actually have this post running on another forum already which is generating some answers but would like some second opinions.

I have a 1991 1Via with an RB25det engine swap. It's paired to an RB25de gearbox.

I'm trying to get the correct speed sensor to fit it and get my speedometer working.

I've got an RB25DET speed sensor which fits into the gearbox hole but doesn't mesh with the Speedo drive because I believe the DET sensor is longer than the DE version and has 20 teeth instead of 21.

I'm lead to believe that the RB25DE speed sensor is actually common / shared between both the RB20DE and DET gearboxes. I have an RB30DE speed sensor and I know that doesn't fit the 25DE gearbox.

What I'm after is if anyone knows the exact part numbers of the below:
RB20DET speed sensor
RB20DE speed sensor
RB25DE speed sensor

Or if anyone knows anything different to the above info with pics.

Cheers Al

Link to comment
Share on other sites

RB25DE box is same box as RB20DET. So cable speedo drive or electronic senders will cross-pollinate between them. The 35DET box is a completely different box, so the speedo sender will not work with the skinny boxes.

As Robbo suggested, the 4cylinder box's speedo drive should be same enough with the Rb skinny boxes, but there's no guarantee that the output speed will be correct. It might be, but I don't know for sure.

Keep in mind that the electronic speedo sender in the box sends an AC signal to the dash. The dash converts that into a ~5V PWM square wave signal for the ECU. So all 3 parts have to be correct to get everything working perfectly. Sometimes near enough will be near enough.

Link to comment
Share on other sites

5 hours ago, Black 1via RB25det swap said:

What I'm after is if anyone knows the exact part numbers of the below:
RB20DET speed sensor
RB20DE speed sensor
RB25DE speed sensor

According to the R32 parts manual they all use the same speed sensor 3270258S21 the 21 on the end indicates the teeth.

Link to comment
Share on other sites

  • 3 weeks later...

Okay guys I have finally sourced the appropriate sensor for the RB25DE gearbox. I now have an RB25DE/RB20det, RB25det and RB30DE sensor. To save any people the future hassle of going through this please see the below photos of the sensors next to each other. I will attach photos of dimensions to so you can know what you're after. The RB25DE sensor is indeed shorter than the 25DET sensor and has 21 teeth on the purple pinion head as opposed to the 20 teeth on the 25DET red pinion head. The RB30DE speed sensor is the greeny/blue pinion head and has a OD of only 28mm as opposed to the RB25 sensors which both have an OD of 30mm to enter the gearbox.














  • Like 3
Link to comment
Share on other sites

  • 1 year later...

Hey I am having a similar issue. Have a gtt Nismo cluster for my r34 GTV, everything works except for the speedo. I believe this to be a speed sensor issue and the difference in teeth on the worm gear. The r34 GTV runs the RB20DE gear box. Were you able to solve this issue with the different speed sensors?

Link to comment
Share on other sites

On 10/01/2022 at 12:23 PM, GTSBoy said:

Shouldn't make any difference. The speedo should work. It might be wrongly calibrated, but it should work.

I connected it up but the speedo doesn't work. i also get the engine code 14 for speed sensor which causes the hicas to lock up and the power steering pump to not work. I have connected my old cluster in and it works fine again. apparently i need the r33 rb25de signal sensor which fits the transmission but sends a larger pulse for the speedo and ecu to read.

Link to comment
Share on other sites

On 1/14/2022 at 12:08 PM, Noble__1 said:

apparently i need the r33 rb25de signal sensor which fits the transmission but sends a larger pulse for the speedo and ecu to read.

I can't see this being likely. As far as I know, all the Nissan inductive gearbox speed sensors output about the same thing - a -1 to +1 volt AC/sawtooth wave, with the magnitude varying a bit with speed, but the main information in it being the frequency.

This goes to the dash. The ECU does not see this signal. The dash outputs a square wave PWM 0-5v speed signal.

You can see all this in the workshop manuals.

Link to comment
Share on other sites

Spin all your sensors with a battery drill and watch the signal on the output wires with an oscilloscope. You'll see what they do. If you don't have a scope, you can use a multimeter set to a low AC voltage. It won't show you the frequency, but you should see a voltage, which should all be similar.

Link to comment
Share on other sites

Noble, I've had this exact issue as you the last two weeks and Ive found heaps of people with the same problem on the forums but never a solution. After heaps of trial and error, Ive worked out why some people can do cluster swaps in 34s and they will work and some can't.


Ill start by laying out how the speed sensor systems work in 34s. They are unlike any other skyline. It all depends whether the base shell was ABS only, or ABS and TCS equipped, whether the car is a GTT, GTV or GT base doesnt matter.


Starting with an ABS only car. The car has three speed signals, one in the diff nose, and two in the front, one for each front wheel. These sensors are used for the ABS system, and the speed signal. All three wheel speed signals are fed into the ABS ECU, a small black box that is under the glovebox area on the passenger side. This box modulates the signals from a raw sawtooth wave to a square wave, and then feeds that modulated square wave signal to the dash cluster for a speed reading. In this case the cluster expects  a modulated square wave signal, and cant read any other signal.


Moving to a TCS and ABS equipped car. In this instance there are 5 speed sensors. Four are for the TCS and ABS system: one on each front wheel and two in the diff. All four of these signals are fed into the TCS and ABS ECU which is in the boot now. These sensors are dedicated to the TCS and ABS system only. The fifth sensor is a dedicated speed sensor that is on the gearbox. This sensor sends a raw modulated sawtooth signal straight to the cluster. In this case the cluster expects a raw sawtooth signal.


The issue comes when you try to swap a ABS and TCS cluster to an ABS only car, or vice versa. The cluster speedo wont be able to read the signal it is receiving. My guess is the Nismo cluster you have is for a ABS and TCS equiped car, and you have an ABS only shell. To solve your issue, find a speed sensor that fits your box and run the wiring direct from the speed sensor to the cluster to bypass the ABS box. The brown wire coming out of the sensor goes to pin 19 on the back of the cluster, and the black wire goes to chassis ground. 


If the issue is the other way round, and the cluster is an ABS only cluster and the shell is a TCS and ABS shell, its a bit harder. You need to source a front ABS only ECU, find the wiring diagram to power it up and run the speed sensor wires to it, and run the modulated output to the dash. More of a pain than anything, I would suggest grabbing a different cluster that is compatible. Hope this helped.

Link to comment
Share on other sites

@Waz1Thanks, that is very helpful my chassis is a ABS only, is there a way to tell if the cluster is a TCS and ABS cluster or does shining a torch into the back of the bulb socket good enough? The nismo cluster does however have all the sockets for it e.g. TCS off and SLIP lights.

Edited by Noble__1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Latest Posts

    • Is there a particular model of the box that is recommended and where are you sourcing it from? This has me pretty interested as well for my 1JZ (currently with the standard A343 box). Also very interested to see how the turbolamik TCU goes. Is Tuned Performance assisting with this too? 
    • I've never used or seen that kit. project mu have a serious reputation in braking but there is a lot of information missing from that listing like type and style of dogbone, is the disc solid or full floating to the hats etc. It also mentions they run '1 synchronised pad per piston' which sounds overly complex solution to a non-problem to me. Also no information on price or availability of replacement pads or rotor rings If I was looking for something that serious I'd go AP racing or perhaps Brembo as they have plenty of users and good availability, but in any case something like Just Jap ATTKD are proven and less than half the price (assuming that listing is USD)
    • does anyone have any experience with the project mu forged sports 4-piston kit for the GTRs? it's a front brake bolt-on kit, 355mm x 32mm forged aluminum 41mm piston 4 pads / caliper from my experience with the brand in the past, they make pretty solid stuff, so i figured this would be a nice upgrade for the R33. anyone here have experience with these? the site search didn't really yield any results, just posts about brake pads, mostly. cheers!
    • I vaguely remember there was something about it when I did my plates/subframe bushes but it might have just been a forum post I read. 
    • Now installed, fun times as the GKtech manual makes no mention of modifying the subframe brackets/brace plates. Needed to lop off the hump as the GKtech subframe bushes are flat and don't have an indent. Heaps of swearing later, it's in 🥳    
  • Create New...