NEED HELP with auto transmission mystery

meck · Aug 19, 2018

I hope someone can give me some hints as to where to go with my problem as I’m about ready to pull my hair out over this one. I bought a donor truck for the engine and transmission to put in my 1997 Ranger. Both the engine and transmission were in good shape. I drove the donor truck for 50+ miles over about three weeks, and it was fine. I pulled the engine/tranny together along with the wiring loom and computer and put them into my Ranger. Now, the engine runs great, but the tranny will not shift right. Most of the time, it starts in first, shifts to second, then stays there. If I stop, go to reverse, then back to the drive position, it will shift from first, to second, to third as it should. Then, if I keep accelerating, it will downshift back to second and will stay there. I did get a code of PO705, so I thought the DTR (neutral safety switch) might have gotten damaged when the engine swung around while on the cherrypicker and jammed the DTR against the truck body. The new DTR made no difference and the PO705 returned. Any help as to what to check on this will be really appreciated. Help!

sheltonfilms · Aug 19, 2018

Need to do a good visual inspection of the harness, could have knicked a wire during installation.

Also the sensor may not be aligned correctly. Should be some methods online showing how to do it. (Why the mounting holes are elongated to allow sensor to be rotated/“calibrated”).

Sent from my iPhone using Tapatalk

Transman304 · Aug 19, 2018

Does the speedometer work? Where does the 1997 set up receive vehicle speed?

meck · Aug 20, 2018

Thanks for your replies. Let me fill in the rest of the story. The donor truck was a '97 OBD2 vehicle. I put it into a '94 OBD1 Ranger. This should be no problem, though, as I changed everything: engine, transmission, harness, computer, underhood relay box, etc. The proof that the change is okay is that the engine runs great. The only thing kept from the '94 was the steering column shifter. I modified the '94 A4LD shifter to match the '97 4R44E shift points on the transmission and they match. To test that this was the problem, though, I disconnected the shift cable, put the transmission into D manually at the transmission and drove it. It drove the same as described in my original post.

The speedometer works fine (it is cable operated, not electronic), using the VSS from the '94. Both '94 and '97 VSS are on the tail of the tranmission.

The nicked wire is a possibility, so I'll spend more time looking. If anyone has anymore hints at all, please let me know. My diagnostic skills are exhausted.

RonD · Aug 20, 2018

DTR sensor tells computer what gear driver has selected, P0705 means computer is not getting any signal from DTR sensor

When you look up codes, look them up on FULL list, never Google a specific code or you won't get the full picture

P0705 Transmission Range Sensor Circuit malfunction (PRNDL Input)
P0706 Transmission Range Sensor Circuit Range/Performance
P0707 Transmission Range Sensor Circuit Low Input
P0708 Transmission Range Sensor Circuit High Input
P0709 Transmission Range Sensor Circuit Intermittent

So computer has these 5 codes it can use for DTR problems, there is a low and a high, a range and intermittent, and then a malfunction, P0705, which would mean no signal at all, because its not low or high, not out of range and not intermittent, its just not there

The cable shifting does need to be adjusted but thats not part of the DTR sensor, DTR sensor is just for computer to monitor the selected gear, the cable selects the gear.

In Reverse do the backup lights come on, that is done thru DTR sensor

meck · Aug 20, 2018

Yes, the backup lights come on in reverse. The truck starts in park and neutral. Thanks for the code information although if the dtr is sending no information to the PCM, I wonder why it is shifting occasionally.

RonD · Aug 20, 2018

The transmission can shift without computer input, it just won't shift well, computer control allows for better shift points based on throttle position and engine RPMs.
In Drive it should shift to 4th(5-speed auto), but would skip 2nd gear, so only 2 shifts.
Starts in 1st then 2 shifts for 3rd and 4th, OD probably wouldn't come on and torque converter wouldn't lock
2nd uses OD so wouldn't work, and RPMs would have to get high for shift to 3rd

I would focus on DTR issue, probably wiring if sensor is new not used

Here is wiring diagram
The Grey/red stripe wire on pin 2 of DTR should have 5volts I believe

meck · Aug 21, 2018

Thank you for the helpful reply and the attached wiring diagram. The DTR is new, so I guess I'll start retracing wires from it looking for damage, etc. The wiring diagram that you sent is for the 5r55e and mine is the 4r44e, but I found the source of yours and got the correct one. It will be a help. I have the Ford wiring book, but it isn't as easy to follow as the diagram that you sent.

Thanks.

meck · Aug 26, 2018

When I test the Gray/Red wire to the DTR, it is getting only .03 volts. When I start the truck, voltage increases to .09 volts RonD said he thought that wire should have 5 volts. The ATSG manual also says 5 volts, but the Ford wiring manual says 12 volts. What I've got is far less than either, and I'm testing the wiring more this morning, but does anyone know how many volts I should be getting. Thanks.

meck · Aug 26, 2018

I can now answer my own question above and add more info that I'm hoping will let someone give me advice as to where to go from here.

The DTR is obviously not getting the voltage that it needs. The light blue/yellow wire (Dig TR Sensor TR3A) and the gray/red (signal return) both are giving me .03 volts in Run. The two wires are connected by the clutch pedal position jumper. When I disconnected them and tested each separately, I got 5 volts at the light blue/yellow wire all the way to the DTR. On the gray/red wire, I got 0 volts. Does this indicate a short in the gray/red wire?

Thanks.

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