The GPS speeds are usually more accurate than the average speedometer. Of course overpasses, bridges, and the hills of southeast Tennessee will block the GPS signals making the GPS speedos read nothing.

Ron68 wrote:

The 4R70W I used had an output shaft that had a drive gear on it. I used a long tailshaft housing from an AOD (Per Corky/Tubo) and an 18 tooth driven gear on my speedo cable. I was able to use the same cable and end from my old C4. It bolted right in and the stock speedo reads correctly. Butt then, maybe the slick GPS setup will be cool too.

As a quick "aside":  I did what Ron did back in 06 when I swapped to the 5.0/AOD.  I used a Ron Morris cable to adapt from the Ford VSS to the stock speedo.  On the trip to Waco last Nov. the speedo went ape a couple of times so I decided to change the cable.  Called LoKar and "Oh yes, we have the correct cable for that setup".  Don't believe it!!  The sent a cable for direct plug-in to the trans...not VSS.  I called and got, "Oh no, we don't make that cable".  So...to the lathe where I did a little mod and now their cable end plugs into the VSS.

 

If that's an aftermarket electronic speedo, and not a later factory one, it should be programmable to suit whatever gears are in the box?? And whatever rear end ratio??

Last edited by 50vert (3/07/2020 10:28 AM)