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  #16  
Old 03-18-2013, 12:42 AM
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Yes, pretty sure that's the park gear

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  #17  
Old 03-18-2013, 01:17 AM
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Quote:
Originally Posted by TheDon View Post


I think what I've found is the park gear.
This may give you some idea of what to look for.



The left is the parking pawl for the 722.4 with the mechanical speedometer, while the one on the right is the one from the 722.3 with the VR trigger wheel (note the 4 tangs that the sensor reads)

I'd be looking for something somewhat similar, but I don't see it in the diagram. It's possible they are using the parking pawl as a trigger. The '85 Cali 617s pull the tach signal off the flywheel teeth so it's possible that there is some double duty thing going on.

It's also possible that there is no speed sensor on the tranny. If the car has ABS it's likely that they're taking the speed signal off the ABS sensor in the wheel.
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W124 Mechanical to Electronic Spedometer-parkingpawl.jpg  
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  #18  
Old 06-14-2017, 05:46 AM
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For anyone requiring speedometers to work for different rear end ratios, you can send the speedo to a shop and have them simply recalibrate it after swapping to your new diff. All you need is a gps and speedo readings at 30 and 60 mph and they can work their magic. Forget about ratio adapter boxes. Cost is the same and no wiring needed (cheaper to recalibrate actually, but not by much).
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  #19  
Old 04-06-2021, 03:52 PM
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Quote:
Originally Posted by atypicalguy View Post
For anyone requiring speedometers to work for different rear end ratios, you can send the speedo to a shop and have them simply recalibrate it after swapping to your new diff. All you need is a gps and speedo readings at 30 and 60 mph and they can work their magic. Forget about ratio adapter boxes. Cost is the same and no wiring needed (cheaper to recalibrate actually, but not by much).
...and you know this because you have done it on an mb transmission?

If I find a mechanical speedometer from a diesel I can just hook it up and not worry about any odd wires, computers or such?
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  #20  
Old 04-06-2021, 04:30 PM
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You dont have to do anything to the transmission. The electronic speedometer just needs a signal. Once you wire it to a signal from a frequency source, you can program the speedo to read various speeds for any given frequency. So just wire the new speedo up to a wheel sensor or similar eg driveshaft sensor. Then calibrate the speedo for that signal. I did it on my 1994 e420 because I swapped the 2.24 for the 2.82. Obviously the speedo was going to be way off. There may be limits to the range of input frequencies it will accept; if you use something that spins a lot slower or more quickly than a driveshaft, then the speedo might not show anything, in which case a converter box would probably be required.
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  #21  
Old 04-06-2021, 04:42 PM
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There is a lot going on in a thread. The 722.6 is electronic and the speedo info is available on the can network. You can buy a little motor that reads an output from the trans and spins the speedometer cable for the mechanical speedo also. This is the situation in my 123 wagon with the 722.6.
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  #22  
Old 03-19-2022, 08:46 PM
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Can you use an ABS front wheel sensor to drive an electronic speedo?
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  #23  
Old 03-20-2022, 06:40 AM
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What electronic gearbox controller will be used to operate the 722.6?

The Ofgear controller has speedometer output.
https://ofgear.dk/userguide/speedoout.html
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  #24  
Old 06-23-2022, 04:37 PM
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So im currently in the process of converting my spedometer from mechanical (93 300d) to electric and I need a little help. The electric spedo im using is out of a 94 e420 and I have a dakota digital gps speed sender that I am trying to use to get signal. Ive got everything hooked up but the spedo wont work so I want to confirm some things.. Does anyone know if the e420 spedo uses a Sine wave or Square wave signal? Also the Pulses Per Mile or frequency that the unit needs? Im also having trouble finding which plug on the back of the spedo is for the signal in, and where the ground is etc.
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  #25  
Old 11-07-2022, 10:11 AM
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So in conclusion if I find an electronic speedo I should be able to bolt it in and hook up the new speedo to the six speed?
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..I also have a 427 Cobra replica with an aluminum chassis.
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  #26  
Old 06-06-2023, 10:40 PM
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Quote:
Originally Posted by Slo_BenzW124 View Post
So im currently in the process of converting my spedometer from mechanical (93 300d) to electric and I need a little help. The electric spedo im using is out of a 94 e420 and I have a dakota digital gps speed sender that I am trying to use to get signal. Ive got everything hooked up but the spedo wont work so I want to confirm some things.. Does anyone know if the e420 spedo uses a Sine wave or Square wave signal? Also the Pulses Per Mile or frequency that the unit needs? Im also having trouble finding which plug on the back of the spedo is for the signal in, and where the ground is etc.
Hey Slo-Benz, curious if you had any success on getting your speedometer working? I'm planning to use a similar setup, albeit use the abs signal or a crank position sensor pulling off a driveshaft weight

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