Hello everyone. First time posting. Looking for some insight and knowledge. Awhile back I bought a 99 ranger 3.0 4x4 for a "quick flip". Not running, and turned out to be a seized motor. So I swapped in a good low milage 3.0 into it and had less then a grand into it. Went to sell it and then found it had no reverse at the first showing. So then I decided I wad going to fix it and do a sas. Well I swapped in a 78 dana 44 and pulled the transmission for a rebuild. Ordered a global transmission rebuild kit with a superior shift kit and picked up a new torque converter. Installed everything back in the truck and went to test it out on jack stands. It goes fwd and reverse but I quickly found issues. I have the OD light flashing, PO743, and PO760 codes. Anyone else run into this issue or can point me in the direction of how to diagnose these further? The OD light flashing means limp code and the PO743 is for the torque converter clutch assembly and the PO760 is for shift solinoid c. Just looking for further help. Thank you

 

Welcome to the forum

Tell me you flushed the trans cooler and lines as well :)

Flashing OD light means computer has detected ratio or electrical issue in transmission and set codes
P0743 Torque Converter Clutch Circuit Electrical
P0760 Shift Solenoid C(3) Malfunction

First..........the 4R44E, 4R55E, 5R44E and 5R55E are all the same transmissions, what applies to one applies to all

First thing to check is the wiring

There are 6 solenoids, A to D or 1 to 4, your choice, TCC and EPC selenoids
All 6 get 12volts with key from from 1 wire
Each solenoid has 1 ground wire that goes back to the computer, computer activates a solenoid by grounding that wire, and with key on computer will "see" 12v on each ground wire and that tells it the wiring is OK

There is a 16-pin plug on driver's side of transmission
Unplug it

Look here:


Pins 1, 10, and 11 are the 12volts
Use OHM meter to test the wiring inside the transmission
Pin 1 to pin 5 should show 9 to 16 ohms,Torque converter lock up
Pin 11 to 12 should be 3 to 6 ohms, pressure control

Pin 10 to each of the 4 shift solenoids SSA to SSD should see 22 to 48 ohms

Also check the wires on the connector, pull on each wire to make sure its secure

Solenoid C(3) is the OverDrive solenoid, did you do the band adjustments?

Good read here on what is on and off when shifting gears: https://atracom.blob.core.windows.ne.../2003_5_50.pdf

Computer can only "see" the electrics working or not connected, and it knows the RPM of the engine and the RPM of the Input shaft of transmission(TSS sensor)
So when computer activates the TCC solenoid and Locks engine to input shaft then BOTH should stay at the same RPMs, if engine RPMs then go up but input shaft RPMs don't exactly match that increase then torque converter is NOT locked
But your TCC code is electrical, not a "performance code like P0741 Torque Converter Clutch Circuit Performance or Stuck Off

And if computer shifts to OverDrive and engine RPMs do not drop enough or at all then it knows OD is not working, so P0760 a performance code
There are two bands that have external adjustments, intermediate band and OD band

 

Thank you very much! So yes I did flush the transmission cooler lines. I also adjusted the bands when I rebuilt the truck as the manual said do. I'll have to ohm out the solinoids when I get home and verify they are all good. I know I'm about a quart low on fluid as I grabbed 9 quarts not 10. I'll add the fluid for proper level and then ohm out the solinoids on the plug.

 

Okay so I went ahead and measured the resistances as you stated. Here are the results
Pin 1 to 5 (Tcc) 11.2 ohms Pin 11 to 12-Epc 4.8ohmsPin 10 to shift solinoid a(pin16)-29.6ohmsPin 10 to shift solinoid b(pin14)-28.4ohmsPin 10 to shift solinoid c (pin7)-27.8ohmsPin 10 to shift solinoid d(pin9)-27.5ohms

I topped off the transmission fluid and the od light flashing wasn't on anymore. I do have an abs light on so I looked at the abs sensor/vss in the rear Differential and it read 1.711Kohms so I do believe that is bad from what I've seen, So it'll be getting replaced. Would that have any correlation to the issues?
I also managed to break the transmission harness when I went to put it back on. So gotta fix that.

 

Well I hooked up the vss/abs on the rear Differential again and the abs light went away so I guess it wasn't making a good connection. I still have the PO743 PO760 codes. I reset the computer by taking the negative off and it still is there. The CEL is the only light on right now.

 

1998-2000 Rangers used the rear axle ABS sensor as the source for Speed Signal, via the GEM module, GEM converts the 25k ABS pulse per mile to the 8k PPM that speedometer, computer and cruise control need/use
So yes, bad connection at ABS sensor could cause some transmission codes in a 1999 Ranger

Have to leave battery negative disconnected for 5min at least or touch the disconnected negative cable end to the positive cable for a count of 5, that will drain all the capacitors in the vehicle which hold most memory, but computer does have non-volatile memory which can only be clear with a higher end OBD2 reader
So not sure you can clear transmission codes that way, never tried

 

I'll start with a new rear abs sensor just to be sure as it's fairly cheap and pretty old as it is. One less thing to worry about. I'll try resetting the computer and see if those two clear the codes. What would you recommend looking at next since the solinoids all seem to be ohming out okay?

 

Definitely need to clear those codes or you will be chasing your tail

As neither would come back on start up and idling............unless computer sees a problem in the electrical wiring to transmission/solenoids
TCC is not used until vehicle speed is above 30MPH
Solenoid C is not used until above 45MPH or higher

 

So update. I got off work early and was able to swap out the abs/vss sensor on the rear Differential. The old one had a bunch of metal stuck to it so a rear Differential rebuild might be in my future. But after that, and resetting the computer by removing the negative and touching it to the positive for 5-10 seconds and we have no more lights! It seemed to shift fine on the stand but like most things we will have to see what happens when I take it down the road for the first few miles. Went to rebleed the brakes in preps and 3 out of the 4 bleeders are stuck 😂. Can't win them all. Thank you for the help and guidance

 

Good stuff

Nice looking Ranger

 

Welp got the rear axle all done and now the transmission is acting up again. I took it down the road and everything was okay. After about 10 minutes I went to accelerate and it downshifting and reved the engine as if I had no 3rd. Eventually slowed down and saw the overdrive light flashing and the truck was in limp mode. I placed it down into 1st on the shifter and it worked fine. Went to back into the garage and I had no reverse! Turned the truck off and then back on and boom. It had no overdrive light, all the gears worked and reverse again. I pulled the codes and I got po732 p1756 p1761 p1000. The only thing I can think is the valve body solinoids has something wrong with it or i messed up installing the superior shift kit. Anyone have anything similar to this happen before?

,.