Hello all I bought a 10/94 7.3 psd about three months ago. When I bought the truck it needed the trans rebuilt. The previous owner had a leak and overheated the trans, welding the forward clutches together. When I first bought the truck I noticed the over drive button wires that go to the shifter were cut so I bought a new shift lever with button from ford. Then I had the trans rebuilt and when I went to drive the truck, it started out in high gear. After that I thought maybe the guy that built it messed up but he said it was electrical. I found the clip on the plug was bad that went to the solenoid pack so I replaced the pigtail. Still same issues. After about a week I decided to take it to a transmission shop. They determined that internally the transmission wasn't built correctly because they could not get it to manually shift in to first gear. So they rebuilt it. Now it shifts manually into first gear but when in drive it will not go into first. They went through all of the inputs and out puts going from solenoid pack to ECM, as well as mlp to ECM and everything reads as it should voltage wise and ohm wise. They came to the conclusion that the ECM was no good and put a new ECM into the truck. Once the new ECM went into the truck, the same problem exists. Then he said it needed to be flashed at ford, so they did that with no results. I would like to note that when I drove it to the transmission shop, my speedometer and tachometer seemed to be working as they should, and also would like to note that I do not have any flashing or dim od light. But the over drive cannot be turned into the off position. When I hooked up my scan tool ( snapon verdict d7) and looked at the data stream for the transmission, the shift range stays in park/ neutral. And my trans range stays at 1st gear no matter where the shift lever is on the column. If someone could please help me diag this problem I would greatly appreciate it because this is my only vehicle besides my Harley and it is getting too cold! I would also like to note that when I bought the truck I replaced all of the fuses and relays in the power distribution box as well as the EEC relay and all of the fuses in the cab.. I am open to sugestions but I need to resolve this trucks issue.. I can't believe that even my transmission shop has never seen this issue and doesn't have an answer for me.. I'm kinda upset that throwing parts at it was the answer for them so now I am taking this matter into my own hands

Thank you for your time and if I remember anything else I will post

 

Starting in high gear means there is no power to the shift solenoids. Get a wiring diagram for the transmission connector and check if there is +12v at the pins that should have +12v.

 

Is there any way that you have a diagram for the solenoid pack? The trans shop said that they checked all of the wiring and it is perfect.. But I will have to check it myself.

 

I have found what the wires are for, ss1ss2 ect, but I can't find what they should be reading as far as voltage goes

 

Jake9473,

Mark, keep me accurate here….

With the ground test lead on pin 8 (the return), you will see +12 volts on pin #3 when Solenoid #1 is signaled.

With the ground test lead on pin 8 you will see +12 volts on pin #2 when Solenoid #2 is signaled.

As Mark says earlier, no volts to any of the solenoids mean both solenoids are open and the trans is being signaled for 4rth gear.

Volts on both pins means the trans is being signaled for 2nd gear.

S1 hot and S2 not, means first.

S1 not and S2 hot means 3rd.

 

Now what exactly are ideal conditions for testing this ? Koeo ? Or koer with wheels off the ground? I am a diesel tech, but I'll be honest, if it's anything electrical at our shop there is a guy designated for that, my forte is the 7.3 powerstroke engine, never did learn much on electrical diag, so this is new to me, and as far as working on it at work, I can't afford the 98 dollar shop rate !

 

Also if I find that the wrong sol. Sensor is being signaled, how do I correct the problem? It surely can't be as easy as swapping wires? Or could it?

 

Again I'll defer to the knowledgeable folk here, but key on engine off, with the vehicle safely chocked from rolling, should give you the different signals at the at the pins.

I highly doubt you have the wrong pins signaling the wrong solenoids

Something is whacky. There is no "manually shifting into first".

I believe what you are saying is "when I pull the column shifter into 1rst the trans shifts into 1rst" but this is an electrically actuated event. Meaning that the S1 (pin 3) is being signaled with voltage.


First, check to see if you get voltage across on Pin 3 (for S1) and pin 8 or any of the other pins (in case I'm wrong on pin 8 being the Return ground) with the ignition on and engine off, with the column shifter in 1rst or 2nd as these both signal S1.

If this proves to be successful, go to the next step. If it does not, something isn't right, either your truck or most likely my directions. Please stop and wait for Mark to chime in.

If successful, check to see if you have voltage on pin 2 with the column gear selector in 2nd and 3rd (Drive) as these both signal S2.

 

My ignition cylinder is also broken and the wire going to it from the switch is removed could this play any factor in the electrical issue?

 

I really appreciate the help. Mark do you have anything to add?

Also Leo what exactly do you mean when you say
Something isn't right as far as my truck goes? Wiring or something? I'm sorry for the ignore ce but the electrical
Side to things is about equivalent to me trying to read Spanish.. (Zero)

 

Jake, I don't know about the broken wire at the switch.

I've studied up on the solenoids and their sequence recently for a small project I have in mind, but am out of suggestions at the moment.

I was commenting in general about something not being right. I don't think the problem is something functioning wrong, or wires now need to be swapped, I think something is just plain old broken.

Unfortunately your shop isn't able to help you, most likely they just don't know how, but that sucks.

 

Well I pulled all of the loom to all the wires going into the idm ECM power distribution box, and other relays under the hood, cleaned all the plugs, and packed them with dielectric grease. Plugged them all in and cleaned all my visible grounds.
when I turned the key on, I noticed my over drive off light briefly flashed as if it was now getting power.. So there's some progress I guess... Now, Leo. I did notice after test driving around the block here that whether the column shift lever is in 1 or 2 it starts in second gear, and when in d or 3 rd gear, it is in 3 rd gear. But now what worries me is when I turn the key on, the wait to start light, check engine light and door buzzer all flash and click like a metronome as well as what sounds to be the glow plug relay, and when I go to start the truck the starter clicks really fast as if the batteries are completley dead. But both are charged... So now I am stumped! Any input would be greatly appreciated

 

I edited an earlier post for accuracy. Again, all of this is based on my reading, I have little practical experience with this and defer to those with more knowledge.

James, Sure sounds like solenoid #2 is not actuating the 2nd or 3rd gear. Whether it is the trans internally, the solenoid isn't getting voltage or the solenoid itself is broken, I don't know.

I'd suggest getting the flashing lights, etc solved first. How many volts do your batteries have? Does the voltage drop when you key on or try to crank?

Maybe someone else has some thoughts about this..

 

If it were me I would get that ignition stuff fixed first.it is looking like a power issue that is power on issue.that needs dealt with before any specific testing is done. Check all ignition power on all the time and key on outputs.you just might fix your issue by accident.