94 GT with a 99 T-5. Works, but speedo is way off..Help!

I recently traded a dirt bike for a 94 GT 5.0 with a T5 in it. The T5 works and shifts, however the speedo reads 150 when its going about 30.

I looked at the tag on the trans housing, and I have:

XR3R-7003-DA-REP-BF
and
1352-260-051641-K1891

I found that this transmission is from a 99 Mustang v6.

I pulled the speed sensor and it looks like this:

DSCN3717.webp


I spun the rear wheels from under the car and counted the revolutions of the drive shaft and I have determined my car has a .373 gear in it.

What do I need to make this work? Different speed sensor? different speedo drive gear? original speed sensor from the 94?

Please help
 
well I dont know if its possible but I dont think that sensor will work for you. Your best bet would be to pull the extension housing off and swap in the correct plastic gear and speed sensor from a 94.

So, you can switch over to manual speed gear? That will invove changing over to the old manual style. Changing over to old style speedo cable,manual gear, and cover? With parts from 89-95?
 
So, you can switch over to manual speed gear? That will invove changing over to the old manual style. Changing over to old style speedo cable,manual gear, and cover? With parts from 89-95?

no remember the sn isnt cable driven its electrical but the sensor itself has a plastic gear that runs on another gear on the mainshaft. So the only thing you would need is an sn speed sensor(94-95) and the plastic gear that goes on the main shaft. Or as stated before you could get a speedcal.
 
Ok I ordered a speed cal and I have it here sitting in the box. I am reading over the instructions, and my first question is this: Will this work with my speed sensor that is from a 99 3.8l T5? (Trans code 1352-260) Take a close look at the sensor in the picture above. It is not the same as the 94-95 electronic speed sensor with a gear drive. You will notice that the housing is broken off, but here it is at advance auto with the housing:

Sensor - Vehicle Speed by BWD - Part SN7143 - Advance Auto Parts

There is no gear on this sensor anywhere. It is simply a magnetic halls effect sensor.

So how do I program my speedcal considering the following:
My original car was a 94 GT with a T5 and a 3.08 gear and stock tires.
My current car is a 94 GT with a T5 from a 99 3.8l a 3.73 gear and stock tires
 
Update...apparently there is one person in the world who holds the secret code for this. And it is Justin at Dallas Mustang. I have to install the speedcal with the dipswitch on in locations 1 and 4, then reset my trip odometer, then drive for a known distance calculated by a gps or pace vehicle (min. of 10 miles) then call Justin back and tell him what my trip odometer says. From there he inputs this information into an excel spreadsheet and out comes the correct code.

Wow.