Trouble code 647

[stangconcepts]

Hello, My name is rich and I have a problem. Sounds like an AA meating, anyways, I am new to this forum and have a problem. I have a 1995 explorer XLT with the 4R55E trans. I just put in a used trans from a 1996 ranger and now I get code 647 ( improper 3rd gear ratio) What the hell is this? I have not adjusted the shifter yet and it will go into 2nd if it is in drive and not shift but if I put it in drive it will shift. Is the problem the gear selector on the side of the trans or will this trans not work? All the help is very appreciated and I hope to be here for a long time. Thanks Rich :exp:

 

[Glacier991]

First off, I will tell you I am not the guru on here for swaps.... lots of others have experience. When you DO swap a tranny you should try and reuse your old sensors though. That is my first piece of advice. My 2nd is that "used" jinkyard trannies have an inordinately high failure rate... so much so that I recommend against them. Finally, I do not find that code (PO647) in the FORD manual for the 4R55... not that it does not exist, but my bible is silent.

 

[Glacier991]

btw, welcome to the site....

 

[stangconcepts]

This was not from a junk yard. This is a known good tranny. I am not sure if one of the sensors is different or not but thanks for the advice.

 

[MrShorty]

http://www.troublecodes.net/Ford/ lists a 647 as a CM EEc-IV code for that problem.

I probably know less than anyone here about the 4R55E. I do know that your '95 will be EEc-IV, where the '96 donor vehicle would be EEC-V. I don't know anything about swapping from a '96 to a '95, but I wouldn't be surprised if there is some wiring difference between the transmission and the PCM that doesn't allow your computer to see the speed sensors or control the shift solenoids. Unless someone more familiar with the two setups can point you in a better direction, you might have to sit down with the wiring diagrams for the donor vehicle and the recipient vehicle and see if you can identify any differences in the wiring scheme.

 

[stangconcepts]

IS there any difference in the 1995 4R55E and the 1996 4R55E trans? Has anyone done this swap with any or no problems. I can clear the code and it takes a while to come back. The only other problem with the truck is a bad O2 senser and I know that has nothing to do with it. Please somebody must know. Thanks Rich

 

[Glacier991]

I do not believe the trans themselves are different... but Mr. Shorty is correct (as he always is) about the EEC4 to 5 upgrade. I would think you could use the 96 4R55E and swap in the 95's sensors... it might NOT be necessary, but that would be your safest bet. Beyond that I cannot offer much advice.

 

[stangconcepts]

Which sensors do you think I would need to change? The gear selector or all the selonoids and everything?

 

[MrShorty]

It's intermittent? That suggests that, at least some of the time, the computer and transmission are communicating as well as the computer expects. With this new piece of information, I'm not entirely sure that anything needs to be changed. As pulling codes is only one step in a thorough diagnosis, what are other symptoms? Does the transmission shift through all the gears? Does it slip? Any other symptoms to report? Can you identify any common elements that precede the appearance of CM 647?

An intermittent problem like this is often an electrical issue (loose connection, broken wire, etc.) Are you certain everything is plugged in tight? Clean connections? Any obvious wiring issues? Finding intermittents can be a real challenge, because you have to be looking at the fault when it occurs.

 

[stangconcepts]

I can find no problems with the electrical. I have cleaned all the plugs and made sure thay are tight. As far as other problems, It shifts fine through all the gears, goes into overdrive and the converter locks up as it should. It does not slip or shift hard. It only shifts hard when the od light flashes but from what I have read that is because it is in limp mode. I have a scaner and have checked it and I have no other codes other than the O2 sensor.The other code is 172,EGO not switching on bank one.I know the trans was good as I know the truck it came out of and it was fine and well takin care of. Thanks for all the help so far. Rich

 

[Glacier991]

You could be showing (and tripping into LIMP mode) on a proprietary code that your scanner is not able to read. (codes in the 1xxx series are proprietary FORD codes and few home scanners can read them....) This is a curious one, for sure.

 

[stangconcepts]

I would think that my brothers very up to date snapon scanner would read all the codes. That is all it picked up. He is a mechanic but doesnt know transmissions that well. But I have had his scanner pick up things the local ford dealer did not pick up.But our dealer sucks to.I have not had the od light flash again since I cleared the codes and adjusted the gear selector and the wife took it on a 300 mile trip this weekend. Maybe I got lucky.(fat chance but I can hope). I am going to call a buddy tomarrow that is a ford mech and see what he thinks. Thanks for your help this far.

 

[MrShorty]

Are there such things as prorietary codes on EEC-IV/OBD-1 vehicles? This is the first time I've heard that possibility mentioned.

That's the tough thing with intermittents. If it seems to have gone away, the best thing to do might be to drive it until the problem returns, or until it becomes more consistent so it can be diagnosed.

 

[Glacier991]

Are there such things as prorietary codes on EEC-IV/OBD-1 vehicles? This is the first time I've heard that possibility mentioned.
/QUOTE]

Actually (blush) when I posted that I was seeing a 3 digit code and assuming it was EEC-V. HOWEVER, I honestly do not know if whether when EEC-IV went to 3 digit codes it did not also have proprietary codes as well starting at that point. Probably not, but it is an interesting Q, now that you bring it up. Anyone know when proprietary codes first appeared? (Save me some research time if you do.)

 

[stangconcepts]

I believe that adjusting the range selector and clearing the codes fixed the problem as I have put over a 1000 miles on it since and no code yet. I hope this helps other that have had the code. Thanks for all the input. Rich