Is it possible to transfer a speed sensor from one transmission to another?

Hey guys, new here this is my first post. I have a 2003 Protege5 with a manual transmission. A couple of years ago the transmission died and I had to swap it for another one that I bought on Ebay and had my mechanic put in. At the time I was aware of the two different types of transmissions for the car, one with a speed sensor and one without, and the guy on Ebay assured me both would fit. (I assumed that my mechanic could just take the speedsensor for my old broken transmission and put it into the new one that I got off Ebay that DIDNT come with a speedsensor attached). Turns out he couldn't do it so I was left with a running car that doesn't have a working speedometer that can't pass a smog test. Car's been sitting in a lot and I'm finally ready to work on it again. Been talking to a new mechanic telling him I'm going to have to buy whole new transmission with a speedsensor and swap it again to make it work finally - he told me that I might be able to just get a speedsensor from another protege5 transmission and mount the sensor onto my tranny that didn't come with one. Is there any truth to this or is he wrong?

tldr: I have a manual transmission model that comes without a speedsensor, that is already installed into a Protege5 that originally had a transmission WITH a speedsensor. Can I grab the speedsensor off another protege5 and mount it onto my transmission? OR do I need to swap in a whole new transmission that comes with a speedsensor originally?
 

pcb

The Diagram Dude
:
2002 MP5
My memory is a little foggy on this, but I remember that there is a little pink plastic gear set that can be installed into your transmission, but the transmission needs to removed and come apart to install the one gear.

I believe the transmission needs to be partially disassembled to install the one gear onto a shaft inside the transmission.

There is either a plug to be removed, or a hole that needs to be drilled to get the gear assembly through and into the transmission.

There is information on all of this buried somewhere back in the old threads, but the pictures may no longer be showing in the threads.

Cars that come with ABS, use the information from the ABS system to provide speed information to the ECU and speedometer.

ABS info is more accurate.
 
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...Turns out he couldn't do it so I was left with a running car that doesn't have a working speedometer that can't pass a smog test.
What does a working speedometer have to do with a smog test? Are they talking speedometer, odometer or both?

I bought a cheap digital GPS off eBay or Amazon for like $15- and plugged it into the cigarette lighter to read out speed until I fixed my wife's speedometer (re-soldered bad solder joints).

Another reason to move to Florida - no car emissions tests.
 
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What does a working speedometer have to do with a smog test? Are they talking speedometer, odometer or both?

I bought a cheap digital GPS off eBay or Amazon for like $15- and plugged it into the cigarette lighter to read out speed until I fixed my wife's speedometer (re-soldered bad solder joints).

Another reason to move to Florida - no car emissions tests.
I believe the non working speedometer is causing the check engine light go off which results in an automatic fail of the smog test if I'm not mistaken.
 
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Thank you so much man, I read through it. Also replying to your previous comment, and editing my whole original post:

I just realized that my car is a NON abs and NON trans mounted speedsensor 2003 Protege5 model. I'm not sure why the original swap didn't work but I'm assuming it's because either it came from a regular Protege and not a Protege5(like the guy in that thread mentioned) or that I tried swapping in a trans with a speedsensor into my car that originally came without one.

Judging from that thread I'm assuming my best option at this point is to just source a new used trans and swap that in, this time making sure its coming from a Protege5 thats non ABS and no speedsensor on the trans.
 
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pcb

The Diagram Dude
:
2002 MP5
I just realized that my car is a NON abs and NON trans mounted speedsensor 2003 Protege5 model.

That's not right.
If your car is NON abs then the ECU has to get the speed info from the transmission.

Your car must have gotten it's speed info from the transmission if it doesn't have abs.


If your car had abs and you installed a non abs transmission into it, everything would work fine.
The transmission speed info wouldn't be used and the car would use the abs info instead.


(There may be a different ECU used to process the different speed info from either the abs input or the transmission speed gear info, but I think the ECU can process either speed input info.)
 
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That's not right.
If your car is NON abs then the ECU has to get the speed info from the transmission.

Your car must have gotten it's speed info from the transmission if it doesn't have abs.


If your car had abs and you installed a non abs transmission into it, everything would work fine.
The transmission speed info wouldn't be used and the car would use the abs info instead.


(There may be a different ECU used to process the different speed info from either the abs input or the transmission speed gear info, but I think the ECU can process either speed input info.)
"If your car had abs and you installed a non abs transmission into it, everything would work fine."

And what if it was the other way around? Say I have a non abs model and I swap in an ABS transmission. Would that mess with the speedometer and speed reading?

I reached out to Mazda just to make sure what model I had, and they verified that I originally have a NON ABS transmission. I'm assuming the issue was that I incorrectly swapped in a transmission that had an ABS sensor. Could the issue be something else entirely???


(also I'm assuming that if a car has ABS it also has a trans mounted speedsensor? I'm wondering if they come as a gauranteed pair, meaning a model with NO ABS would definitely not have that trans mounted speedsensor)

Thanks a lot for the patience. I'm learning, and I don't want to have to eat the cost of yet another transmission if I get an incorrect one installed for a second time.
 
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pcb

The Diagram Dude
:
2002 MP5
"If your car had abs and you installed a non abs transmission into it, everything would work fine."

And what if it was the other way around? Say I have a non abs model and I swap in an ABS transmission. Would that mess with the speedometer and speed reading?

Yes,
Yes it would .

Your ECU would have no speed sensor input.

An abs car doesn't have the gears in the transmission to send info to the ECU.

I reached out to Mazda just to make sure what model I had, and they verified that I originally have a NON ABS transmission. I'm assuming the issue was that I incorrectly swapped in a transmission that had an ABS sensor. Could the issue be something else entirely???

No,
That is your issue entirely.
That's exactly what you did !..

You bought an ABS transmission with no speed gear.

(also I'm assuming that if a car has ABS it also has a trans mounted speedsensor?

NO !!!

That's Bass Ackwards !!!

If a car has ABS, it doesn't have a speedo gear because it gets its speed info from the ABS sensors.

If you don't have ABS sensors, you get your speed info from the speedo gear on the transmission.

If you have ABS, you do not have the speedo gear on the transmission.

I'm wondering if they come as a gauranteed pair, meaning a model with NO ABS would definitely not have that trans mounted speedsensor)


Again, that's Bass Akwards...

A Protégé with no ABS simply must have a speedo gear from the transmission, or the ECU will get no speed info...


They are a guaranteed pair.


A model with NO ABS would definitely have that trans mounted speedsensor...
 
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pcb

The Diagram Dude
:
2002 MP5
My parts car has a toothed ring and sensor on the CV joint...
It has ABS.

20210622_184904.jpg


20210622_184827.jpg





Cars that have ABS, have a toothed ring on the CV joint.

Screenshot_20210622-190123_Brave.jpg




Cars that don't have ABS, don't have a toothed ring or sensor on the axle...


Screenshot_20210622-190302_Brave.jpg
 
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pcb

The Diagram Dude
:
2002 MP5
Cars with ABS have 44 pulses of info for every rotation of every tire.

Cars without ABS get just a few pulses of speed info from the rotation of the axle...

That's why they use ABS info over axle info when available.


It's way more accurate.
 
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pcb

The Diagram Dude
:
2002 MP5
Find a 2 liter Protege without ABS to get your transmission transplant from.
(maybe other models/years too?)

It will have the speedo gear installed, for you to attach to.
 
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Yes,
Yes it would .

Your ECU would have no speed sensor input.

An abs car doesn't have the gears in the transmission to send info to the ECU.



No,
That is your issue entirely.
That's exactly what you did !..

You bought an ABS transmission with no speed gear.



NO !!!

That's Bass Ackwards !!!

If a car has ABS, it doesn't have a speedo gear because it gets its speed info from the ABS sensors.

If you don't have ABS sensors, you get your speed info from the speedo gear on the transmission.

If you have ABS, you do not have the speedo gear on the transmission.




Again, that's Bass Akwards...

A Protégé with no ABS simply must have a speedo gear from the transmission, or the ECU will get no speed info...


They are a guaranteed pair.


A model with NO ABS would definitely have that trans mounted speedsensor...

Again, thank you for the clarity. I don't know how I got this confused but it was tricky to figure this out online on my own. I get it now.

Even the Mazda support chat person told me that my car has NO ABS and also NO trans mounted speedsensor when I asked her for that specifically.

I'll be ordering another used trans for my Protege5 now, and I'll be double checking that its a NON ABS model so it fits into my original car with a working speedometer.
 
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pcb

The Diagram Dude
:
2002 MP5
Even the Mazda support chat person told me that my car has NO ABS and also NO trans mounted speedsensor when I asked her for that specifically.

She's wrong.
The ECU needs speed info.
Either from the ABS or the tranny gear...
I'll be ordering another used trans for my Protege5 now, and I'll be double checking that its a NON ABS model so it fits into my original car with a working speedometer.

Make that clear.

You want a transmission with a gear output.

Maybe try to find a picture of that output to verify.
(I don't know what it looks like?)

Remember, the transmission output gear feeds your speedometer/odometer...
 
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