The Stovebolt Site Forums The Parking Lot Big Bolts Electronic speedo w/ 2 spd rear

I have an electronic sender on the trans and electronic speedo.
I have a 2 speed rear end.

For a cable speedo it is no problem... Just install a speedo "transmission" in line to the speedometer cable and you're good to go.



For the electronic?
Does anyone make a box that accepts a "low range" input (from the 2 speed shift switch) that will change the speedo ratio?

Other solutions?

I cant imagine any mod was made for original 2 speed rear trucks- the speedo was probably correct in one ratio and wrong in the other? Make a different set of marks on the speedo for the incorrect range?

anyoldiron, from the factory 2-speed rear trucks were equipped with a speedo adapter that was electrically or vacuum operated to change when the rear was shifted

journeyman, never seen such a devise for electronic trans/speedo, but if there were such in the US or Canada, I doubt they'd ship to Russia right now

Bill

I'm not sure if there is a cleaner solution, seems like there ought to be something available from a later model medium duty truck with 2 speed rear...

But this may work with a switch to put it in or out of the circuit as you shift the rear axle.
http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/

I've seen the Dakota Digital 5 unit and am talking with the tech there. It is unclear whether it will work with the two different R&P ratios.

I have even considered GPS units (Dakota Digital or Classic Instruments' "SkyDrive" SN81. I would feel more comfortable with something driven off the vehicle itself.

I am considering purchasing a ABS ring and sensor and machining one of the front hubs to accommodate it, but that seems like a lot of effort and who knows if the ring (1999 P30 Chevrolet) would fit even with machining?
A bit of a risky purchase.

...also, the project is in California

The late model truck part is a great idea.

What would this unit be called?

I think if anyone would know, these people would know.

http://www.zepco.com/

They used to make all kind of speedo and tach adapters for me. Of course now the speedo sensor sends a signal to the ECM and the ECM is programed to send a signal to the speedo.

Do you have a tachometer? If so, it might be possible to come up with an equivalent RPM/speed range in both axle ratios and make a set of stick-on pointers on the tach face corresponding to different speeds. Not a perfect solution, but it might be a good approximation.
Jerry

Install two of the Dakota units and calibrate one for each rear ratio. Wire the two output signals (one from each unit) to the speedometer. Have the 2-speed rear selector switch turn on and off the correct unit to match the rear.

Mike B

You and I are thinking about the same thing Mike.
With any luck the actual electronic speedometer can be programmed for one correct speed/ratio, and use one Dakota Digital either in series with the normal sender or removed from the circuit to make a change in the pulses equal to the ratio change in the rear axle.

I may have found a ray of hope.

As Grigg mentioned, later model (1990's) topkicks had all electronic speedos and also were available with 2 speed axles.

From what I understand, There is a "buffer" of sorts that gets a signal from the hi-low switch and keeps the output to the speedo accurate.

I am looking for a part number or even a name for this component. All I have now is "VSSB" (buffer) module. I have had no luck searching for it on google. One place called something a "VSS corrector".

I really need to find a part name and part number for this. It really should not be this much effort.

Anyone on the what this part might be called?

Not sure why this is so difficult for me to find...

I think I may have found a possible solution:
Dragonaero speed adapter

I have never heard of this company, but it seems like this is exactly what I am looking for.

Any input?