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I am new to the forum - I do belong to a mustang forum (1971 mustang) and ford truck (1997 OBS Diesel) so thought maybe i could ask for some help on a Ranger forum.
I bought my son a 2001 Ford Ranger 4x4, 4.0l, a couple years back as his first truck. Worked great for a year, then one day coming home from bucking bales, his transmission started shifting funny and he had to manually shift it to get it home. I pulled codes and it had about 4 of them, I remember p0731 (which had to do with 1st gear) but there were codes for 2nd gear, 3rd gear, and I think another. We pulled transmission and got it rebuilt by a friend who used to run his own shop - new steels and frictions, bands and torque converter. Reinstalled, but can't work the bugs out. It was still setting codes p0731 and p0732. We pulled back transmission back out and replaced a sensor in the case (maybe a speed sensor?) and neutral safety switch. Reinstalled. Still will not shift into first when placed in drive but will shift into 1st manually. Sets code p0731 and o/d light flashes. We pulled pan and replaced all the shift solenoids and checked them and they had 11.9V with key on. Reinstalled pan and filled with fluid. Still setting that code. Could there be a PCM problem? I can't seem to find a pcm pinout diagram - does anyone know where I could get one - was thinking maybe it shifts by controlling grounds not power and have a broken wire or trouble with computer. Any help or suggestions appreciated.
Yes, like most of the control systems on newer vehicles, solenoids and relays are controlled by Grounding, or pulsed grounding(PWM)
So all the solenoids in transmission get 12v key on, and each has a ground wire back to PCM
The sensors are VR type so generate their own AC Voltage when active
5R44E and 5R55E are the same, 55E has larger OD Drum for the higher torque on the 4.0l but everything else is the same
And just FYI, the 4R44E and 4R55E are also the same as the 5Rs, the "5th gear" was added by turning on OD while still in 1st this gave a new ratio between the old 1st and 2nd in the 4R, making it a 5-speed, so it was just a PCM software change, internally the 4Rs and 5Rs are identical
Changing the solenoids is fine but it would have been better to change the whole valve body, since the solenoids are just on/off devices, its the slider valves they control that do the actual routing of the ATF pressure, which is what selects the ratios
Was the valve body changed when new the new clutches and brakes were changed?
So it starts out in 3rd gear?
Unless you manually shift to 1st
here is a picture of the connector on trans, in Drive only solenoid 1(A) should be grounded, others shouldn't be
So volt meter between pins 10 and 16 should be 12v(or 14v is engine is running) but 0v between 10 and 14 or 7
If one of these solenoid's Ground wires was bare and "shorting" to ground then that solenoid would be on all the time
BUT................you would get codes like 752 or 757
10-18-2020
