P0741 Code - 02 Explorer 4.0 - 160K miles - Need Advice

[eb2005]

So i have an explorer that has been very well cared for and treated well all of its life. I have fortunately never had to replace a single part in the trans, which from what I have read, is a miracle. I have 160K miles on it and now I am getting the p0741 code, and my converter is not locking properly. It locks from time to time at lower speeds, but almost always will lock if I reset the PCM (shut of engine) and then head down the freeway ramp briskly, but not WOT by any means. When it does lock, it is solid and smooth. It doenst slip. If it unlocks on the freeway, most times it will not relock and then blinking O/D light starts.

I have noticed that there is minor shift flare from 3-4, and in general the shifts just aren't as good as they use to be but they are not alarming or anything.

I have had the fluid flushed (yes, the dialysis type flush on the machine at Ford) 4 times prior to this, roughly every 40K - which is about 4 times more than most people i have read about on this forum who are asking about the same problem. I did take it to an AAMCO reciently where they scanned my code and pulled the pan, changed the fluid and filter. This did not net any improvement. I was able to get under my vehicle and look at the fluid and the pan - which to my delight was clean, although the fluid was dark. (I recently moved to Florida from Michigan and had my Explorer heavily loaded, but no trailer or anything, the vehicle was hot as h3LL in the southern stretch of the trip). There was essentially no debris in the pan, which for 160K miles is a good sign that the friction material is not worn out and that my fluid flushes were not in vain.

So here is where I am at: I have the intermittent converter lockup which I intend to resolve. I have done every bit of work on my vehicle to this point, and I have been working on my cars for 15 years now, so I am not going to just throw money at some shop now. I have searched a ton on this forum and really not found anything that has been a definitive fix for this, so I am to this point which is unfortunately just changing parts.

Should I -

Replace the Valve body with a remanufactured unit first? I know its a wear item, so it should help regardless.

If this doesnt fix it, should I replace the solenoid pack? I understand the solenoids are wear items also.

Should I just replace the pack along with the Valve Body?

I have a basic understanding of how the converter works - there is a hydraulically controlled wet clutch pack. Since when it is engaged, it is a good lockup, I have a hard time thinking the converter is bad - unless someone comes back and says that this is most likely the problem. I have read lots of posts about converters being replaced and the problem persisting.

I am confident I can change all of these myself, although I will need assistance from a friend to pull the trans/converter if that is what has to be done.

I know a reman trans is about $1300 for a 'carry out', but I have a hard time justifying that just yet. If that is really the best route, I guess i will have to consider that, but since I had a clean pan and really a good trans prior to this, I have to believe that I just need to fix the wear items - wear items that it sounds like I have gotten far longer than average life out of.

Thanks in advance for all advice.

Ed

 

[eb2005]

TTT

No one has any input?

 

[eb2005]

Thanks for all the advice...

 

[2000StreetRod]

TCC no lock

There are not that many people that know about automatic transmission internals. The last one I worked on was my 1958 Jaguar XK-150 to adjust the clutch bands.

I have read that if your PCM does not go into closed loop the PCM will not lock the torque converter. Do you have any other DTCs or symptoms indicating you're always running in open loop?

Sorry I can't be of more help!

 

[High_Order1]

Don't feel bad. A lot of my questions go unanswered.

First, before you replace ANYTHING, you need to get hold of the Ford Official Service DVD for your vehicle. Not chiltons, or whatever. Real Deal.

then, run through ALL the pinpoint diagnostics.

Your transmission is more electronic than hydromechanical. You can dump a grand in hard parts, but if you have a failing connector, or for instance, an intermittently bad mid turbine sensor (I forget the correct name), then whatever you stuff in will also mess up.

If what goes into the PCM is garbage, even intermittently, before FMEM takes over, garbage will come out.

I have spent months trying to understand the 5R55S. I take spells, first its' complicated, then I think I grasp it, then something else blows my mind and I start over.

But I do know, you can't service one of these like previous auto transmissions. Line pressure readings are very good, but you gotta have a REAL OBDII interpreter.

A code reader will only tell you whats' set. There are pending codes, and codes that only stay a key cycle or two before disappearing with no idiot light to mark their passing.

Also, you need to see if the PCM is commanding the transmission correctly, in real time. If its' telling the TC to lockup, then look at the trans. If it ain't telling, you gotta look upstream to see why.

That help a little??
-Shawn