Well Rangers we finally had a little success around here. After 3 years of enduring no OD in our basket case, we finally stumbled into a solution. I know there are a lot of posts about people mysteriously losing OD. Our solution after much investigation, was to rig a grounding switch on the 3-4 hot wire from the ecm to the tranny and what do you know we have OD. After talking with friends we figured that the original grounding circuit that closes for OD to happen must have been damaged or lost somehow. I know I'm not explaining the technological aspects of all this accurately, just wanted to lend a little light to what seems to be a common problem with these trucks. Cheers.

 

Welcome to the forum

I assume a 1987/8 to 1994 Ranger with A4LD automatic

It had 2 solenoids, TCC solenoid for locking torque converter above 35mph
And a 3-4 shift solenoid for OD on/off
Yes, they both share one 12volt wire that gets power with key on
Then there is one ground wire for each solenoid that runs to the Computer(PCM)
So 3 wire connector on transmission

Yes, if the ground wire for 3-4 shift solenoid was not good then no OD, but that should turn on the CEL(check engine light) in most years
The computer can "see" the 12v on each ground wire with key on, a solenoid is just a coil of wire, so voltage passes thru it
If computer didn't see the 12v passing thru the 3-4 solenoid it should have set a code for that

 

RonD

Yes A4LD automatic. We did get an intermittent CEL when at high speeds when tranny should have been locking into OD position. Yes we seemed to have stumbled into a solution w/o ever really understanding the problem. Let me ask you what/ why do you think that the computer is not send a ground signal to the tranny ? Does it req a sensor to be tripped for this? b/c we have changed just about all of them buy now. My son now seems to think that there is a bad connection in the steering column cluster (possibly a bad ground) that would do this.

 

What year Ranger?

I didn't think the 1994 and earlier Rangers had the OD on/off button on the shifter

The computer controls the OD, 3-4 shift solenoid
There is a speed sensor(VSS) on the transmission/transfer case, part of the speedometer cable unit, 2 wire sensor
That sensor tells computer the speed of the vehicle
On the throttle plate is the TPS(throttle position sensor), it tells the computer drivers gas pedal input

Those 2 sensors are used by computer to shift into or out of OD

If you are in OD and step hard on gas pedal the computer should turn off OD(shift to 3rd) if speed is low enough for 3rd
If you are cruising in 3rd(steady gas pedal) then computer will shift to OD if speed is high enough

If there is an OD on/off button then its a 12v toggle, when pressed it sends 12v to the computer, one time, if OD was set as ON, then its toggled to OFF, if it was set as OFF then its toggled to ON
So its not a 12v ON or OFF switch, its a 12volt pulse, one off, each time the button is pressed
When computer is turned off and then back on OD is set as ON each time

 

RON, THANKS!
It's a 93 ranger so no button for OD. The only thing it has is a selector option for OD on the column gear shift selector.

 

 

Thanks for that but I don't know what I'm supposed to see here.

 

The selector option on shift position display the O and D