Hello to all. A brief history about the truck: I purchased the truck, non-running, it has 220K miles, 4.0L engine, 5R55E trans, 4X4 XLT. When I purchased it, the vehicle was choking on its own exhaust from a bad catalytic converter. I replaced it, and the engine runs well now. After a road test, my transmission is not shifting into O/D. When I push the O/D switch on the shifter, it does nothing. After about 5 min of driving, the trans MIL starts blinking. After that, the shifts through all the gears start to go haywire.... I have already pulled the pan and replaced the valve body assembly with a new one along with all new solenoids. Another issue I have that I haven't been able to track down yet is the number 6 fuse will blow randomly like there is a short, I put my ohm meter on the load terminal, and then the other lead on a body ground.....I didn't get anything out of the ordinary to track down a short, so it must be intermediate. I don't think this issue would cause the problem with the transmission, especially since it works most the time without blowing.

The only codes I'm still getting for the truck are P0734, P0733, P0731, which are still related to the solenoids. I'm at a loss as to what it might be, I've thought maybe the wiring harness inside the transmission? Or the PCM has a problem?

Anyone here able to offer any advice?

 

Welcome to the forum

P0731 Gear I Incorrect ratio
P0733 Gear 3 Incorrect ratio
P0734 Gear 4 Incorrect ratio

These are not solenoid codes, it means the shaft ratios, input and output shafts compared, are not showing the transmission is shifting to lower/higher ratios(gears)

Look here at a full list of Ford OBD codes: https://www.therangerstation.com/tec...II_codes.shtml

Computer monitors each solenoid's electrical circuit, and each sensor's, so it would set another code, like: P0750 Shift Solenoid A Malfunction or P0753 Shift Solenoid A Electrical

Fuse 6(In engine fuse box) ONLY powers the PCM(computers) long term memory, because its blowing it almost seems like a PCM issue, that and the no OD adds to that guess
Does the OD OFF light come on when you press the button?

The OD button sends a momentary 12v to PCM to toggle OD OFF and ON, when PCM first boots up OD is always ON, regardless of what it was when key was turned off

Did the transmission work before changing the valve body with the same codes?
Or are the codes a new development?

I am leaning towards PCM issue

 

Yes, the OD lights goes on and off when I push the button unless the fuse blows. I tried finding the short with the truck powered off by using your test procedure you posted in another post on this forum, but no short was found when I put one probe in the load terminal and the other probe to ground. To be clear, fuse 6 is blowing in the fuse box to the left of the steering wheel where the door closes by the dash....

I foolishly didn't scan the transmission for codes before I replaced the valve body and solenoids, so I do not know if it had the same codes before. But the symptoms are the exact same as before, as if I didn't change anything.

Would a bad wiring harness inside the transmission cause this problem? Would a bad torque converter be a problem here too? Why do you think I'm not getting a P0732 code also?

Also one other problem I forgot to mention about the truck....for some reason the battery is being drained when the truck is turned off......I looked for any lights or anything that may be left on and nothing.....so I don't know if that my point to something that may be coupled with this problem.

When I purchased the truck, the boy I bought it from had given up on trying to get it running, but did tell me the guy he got it from claimed the transmission had been rebuilt and that was a big selling point to the boy. I take that with a grain of salt as to if it had or hadn't, but the fluid was pretty clean when I pulled the pan and I didn't find any debris in it. I also drilled a drain plug hole in the pan, welded a nut on the inside, and put a drain plug on it so I could drain the fluid easily with having a huge mess again for when I have to do any more work on it again.

Thanks for the quick reply and your awesome advice.

 

Then thats a different fuse all together, Fuse 6 in cab fuse box powers several things
Transmission control switch(OD switch)
Transmission range sensor(on drivers side of transmission, on shift linkage), powers reverse(backup) lights
Daytime running light(DRL) module
And if 4x4 the Pulse Vacuum solenoid

Try testing with trans in Reverse, may have a short in the backup light wiring or a bulb

And yes, I don't think any of these would effect shifting

So back to square one
Because of the lack of other transmission codes, i.e. no solenoid codes or sensor codes, its possible the issue is in the rotating parts in the main body of the transmission, outside of the shaft speeds the computer has no way to monitor these parts, only thing it can do is set "ratio error" codes because planetary gears are not working correctly or sprag(one-way) clutches are not working

 

Good idea, i'll try testing for the short it in reverse for the blown fuse issue.

So it sounds like you think my next step should be tearing into the transmission and seeing what mechanical part is bad?

To eliminate sensors as being bad, if it were a bad ISS or OSS wouldn't it throw different codes? Also what do you think about it being just a torque converter issue?

 

I hooked up my friends high end scan computer to read the live data from the PCM as I was driving the truck. I can confirm the TCM computer is reading the ISS and OSS and the solenoid off/on signals. The PCM is commanding the transmission to go into gear 5(od), but the transmission isn't cooperating. I'm going to confirm one more thing that the Solenoids are in the proper (On/Off) configuration for the gears without any errors. So it must be a mechanical issue like you said. I'll take pics during my teardown of the failed part/parts so people can see what was wrong.

 

OK sounds good

There are some tear down and rebuild videos for the 5R55E, which is the same as the 4R55E/4R44E/5R44E and for the most part A4LD, lol, they are all the same transmissions as far as how they work, all based on the C3 trans with OD added

 

Awesome. From your experience are there any must change parts in this transmission when you have it open to prevent further failure? Like new ISS or sunshell(like defective GM ones)?

 

Forward one-way clutch, Front Pump(Ford brand only), and OD Drum if out of round which it usually is depending on miles, and of course torque converter

 

Ok, so I finally got the trans dropped this weekend, and just tore apart today. I can tell it was rebuilt before, the bands look ok, but need replacing, clutch discs looked very good. I think this is the problem, I believe the O/D planetary carrier should be in 1 piece, i think that mine broke apart, not allowing the sprag to lockup the drum.....I took a picture of the overdrive planetary....is it supposed to be in 1 piece with the planetary assembly and the piece going into the sprag?

. Other issues that I thought might be a proble are the servo rod bores on the sides of the transmission, they don't look horrible, but you can tell there is wear.....and there was a build up of material in those servo piston bores. The only other thing I can think of is the incorrect valve body was installed on it(maybe for the 4r44e?). .......can you please look at my pics and see if this is the correct valve body for the 5r55e and gasket? I'm attaching a pic of the valve body with the gasket on top of the plate, and one without. I've also attached a pic of the servo bores I'm concerned about(inside the circled yellow areas where the rod goes through). Also one of the return springs is longer on the side servos than the other(should they be that way or same length). I wasn't paying attention when I was removing them and don't know which one had the longer return spring. There is water on the trans case in the pic because I had just finished pressure washing it, sorry about that. Thank you so much.

 

Sorry I don't know the specific info you need for this.

I am a member over here: https://www.therangerstation.com/forums/index.php

There are a few members that are automatic transmission guys, they may have answers

 

Just wanted to update if anyone has this same issue it was the overdrive planetary race that broke off. I believe its friction welded into place on the planetary carrier. Mine had broken off probably due to a welding defect(reference picture above). I've included a pic of my new/used planetary and what it should look like. As far as the OD/Intermediate servo bore issue, instead of resleeving the case I turned the servos pistons down on my mini lathe a few thous at a time along with cutting in oring grooves on the front and backs of the shafts until they had a nice fit in the bores. This will be a much cheaper/better longterm solution to the bore galling/leakage isssue. I've attached pics of my finished servo pistons.