Electronic output to speedometer

[Ptoneill]

I am not sure if this is the right area for this question......I am looking for a pass thru electronic pickoff that would attach to the automatic transmission's speedometer output, while providing a pass through connection for the mechanical speedo cable. I was able to find one for GM transmissions however it has a 7/8 inch threaded nut which is much larger than the output male thread on the GM transmissions made in France for the Spiders.

I have read about drive shaft pickups that can be programmed to give a signal but I have never used these either. Any ideas would be appreciated!

Thanks

[majicwrench]

Well, not sure what you are creating but.....old cruise systems used magnets secured to driveshaft then a pickup attached to body. Easy to do. I likley have the parts if you are interested.

[Ptoneill]

I am adding a real cool gizmo to my custom 124 and it needs a digital speed input but I want to keep the OEM gauges. I am sort of keeping it a secret until I figure a way to integrate it into the center console. How much would the setup cost?

[majicwrench]

Old magnet and pickup will likely produce a sine wave, will that work?? I put in a bunchof cruise controls, likley have some magnet and pickups left over, will look Monday at shop. If I've got em won't cost much of anything.

[Ptoneill]

The directions don't really say, although the manufacturer uses an auto loc pass thru system, the problem being that their GM module had a 7/8 in attachment nut. Let me get hold of the manufacturer to see what the requirements are, I could possibly make a rectifier to pulse the signal.