Speedometer issue with V8 swap

Broosedamoose · Mar 29, 2017

Ok, so I know the issue is that when I swap in the 99 Explorer motor and tranny into my 03 Ranger the speedometer signal comes from different locations. The Explorer from the the rear differential and the Ranger from the OSS. So what if I just swap the Explorer rear axle as well? Won't that solve the speedometer issue? I already know the shock mounts will need to be moved but that not a big deal.

win · Mar 29, 2017

Nope, the Expo actually used the ABS system for its speed signal and the ABS system uses the same sensor in the back axle as the Ranger.

Couple solution options:

The later 4 cyl Rangers use their GEM to process the abs data to a speed signal. Can be fitted/wired in to replace the current GEM.

Graft in the abs and g_force sensor from an Explorer

Replace the output shaft and tailcone on the transmission to use a VSS

I've read Dakota Digital has a solution

Broosedamoose · Mar 30, 2017

"2001-Newer Rangers: The problem comes when you drop the 5.0L Explorer engine in to a 2001 and newer Ranger. Starting in 2001, the Ranger gets its raw speed signal from the OSS (Output Shaft Speed) sensor on the transmission/transfer case. The OSS sensor is a magnetic pickup that provides transmission output shaft rotation speed information to the PCM (Powertrain Control Module) where it is corrected for tire diameter and axle ratio. The PCM uses the OSS sensor signal to help determine EPC (Electronic Pressure Control) pressure, shift scheduling and TCC (Torque Converter Clutch) operation. The PCM generates a 0~12V square wave. This frequency of the square wave is corrected to provide a standard 8000 pulses/mile using multipliers flashed into the PCM for axle ratio and tire diameter. It is sent to the speed control and the cluster. In this system the PCM is the correction and distribution point for the VSS signal." Taken from the tech article: 5.0L Explorer EFI Swap

So then the above is not correct? Damn, I was swapping it out for disc brakes and had hoped it would solve the issue. Oh well, back to the chalk board! LOL!

win · Mar 30, 2017

Hmmm....Best I can tell, that quote is 100% correct. but --- the OSS referred to is in the transmission.

So, when the Ranger's PCM and transmission come out for the swap, the speed signal goes with it.

The OSS in the transmission and the ABS sensor in the back axle are two different parts, doing two different things.

I've never understood why Ford chose to add the G-Force sensor and the use the ABS/G-Force for the speed signal when they could have simply programmed the PCM to pull the same data from the transmission and generate the signal for the cruise and speedometer like most of the rest of their product line.

Broosedamoose · Mar 30, 2017

Ok, I'm lost! If the Ranger is getting the signal from the OSS in the transmission (which is coming out) and the Explorer gets the signal from it's rear axle ABS sensor, why would swapping the engine, transmission, PCM AND rear axle from the Explorer not work when it goes into the Ranger? What am I not understanding? :icon_confused:

win · Mar 30, 2017

What is getting missed is that the Explorer ABS system supplies the speed signal not the PCM.

So, when the 5.0/4R70W/PCM get pulled from the Expo, they leave behind the ABS generated speed signal.

When the Ranger engine/trans/pcm get pulled from the Ranger, they take the pcm generated speed signal with them.

Mix the two and you get a 5.0 powered Ranger with no speed signal and needing one of the solutions I'd posted earlier.

Broosedamoose · Mar 31, 2017

Aaaaah, I see said the blind man! :yahoo:

LOL! So, if I pull the ABS system from the Explorer and swap (graft) it into the Ranger along with the motor, tranny, PCM and rear axle it should work? I intend to take the Ranger right down to the frame and then work my way up from there so it's getting all new brake lines anyway. I am considering swapping out the entire Explorer electrical system to the Ranger so I can have the climate control, power seats, console, etc.

RonD · Mar 31, 2017

1999 Explorer with 4wheel ABS speed signal
VSS(rear axle)------------4WABS module-----------splitter/splice----speedometer(computer and cruise)

1999 Explorer Rear ABS only speed signal
VSS(rear axle)------------GEM module-----------splitter/splice----speedometer(computer and cruise)

2003 Ranger speed signal
OSS(trans/transfercase tailshaft)---------computer---------splitter/splice----speedo(cruise)

Rear axle VSS needed to be corrected for tire size to send True Speed to speedometer and computer(cruise doesn't care but gets true speed anyway, lol)
So 4WABS module would do that OR on RABS GEM Module would

Trans/transfer case speed signal needs to be corrected for axle ratio AND tire size to get True Speed for speedometer.
On 1997 and older this was done by changing the speedometer gear in the trans.
In 2001 and up this was done by the Computer(PCM).

You can also skip all that and use a Dakota Digital SGI-5E, there are other brands of these as well
It is a signal interface, it takes what ever speed sensor signal you have and converts that signal to the 8,000PPM(pulse per mile) expected by Ford Electronic speedometers.
These can be fine tuned for changes in tire size and/or axle ratios.

Broosedamoose · Apr 1, 2017

I checked out the SGI-5E and it's not expensive at all! Has anyone around here ever used it?

As for the PCM, I can do whatever I want there. I have the ability to change whatever I need with either the tune or thru a J2534 interface. I own all the equipment.

RonD · Apr 1, 2017

PCM won't have True Speed correction in '99, '01 and up did I think
For '99 it was GEM or 4WABS

"Hicks60" and "Tab a" both recently got the SGI-5E working on V8 conversions, took a bit but they did get it working

You could probably PM them to get exact wiring they used

Do a Search for: Dakota Digital
And you should see their threads in the V8 Forums

Speedometer issue with V8 swap

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