Newbie :) No overdrive PSD tranny

[Urayo]

Hi guys this is my first post here hope someone can take me throughout the right direction. My rig is a 2001 250 7.3 PSD with 75K miles I was driving along the motorway when suddenly my overdrive came off, this happen after a toll stop, the thing is that the trans. isn’t shifting the overdrive also a few minutes after the overdrive light began to flash. After that I stopped immediately and checked if there were any leaks on the trans. but none, after the stop when I shifted from drive to park I noticed the RPM’s went up for about 1sec probably 200 RPM’s from normal (this happened once). I also checked the trans fluid level and it was ok. I then turn off the engine to see if it will reset somehow the overdrive flash and it did but the trasn. still wasn’t shifting to overdrive. What kind of trouble shooting do you guy’s recommend to start with? Any fuses, solenoids, relays, sensors ? Any help I will greatly appreciate.

P.S. The truck is stock except for 4” exhaust.


Josue

[Banshee34]

Have you pulled any codes?

I am by no means an expert but everyone has told me when you O/D light blinks, the tranny is done... hope this isn't the case for you.

[Urayo]

Not yet , maybe tomorrow I will take her for a code scan.

[Maintain]

I think another option would be the O/D switch on your column. It unscrews and there are a few wires inside that connect to the button. This may need to be replaced. I had a similar problem, where my O/D light started blinking however my O/D was working. I had gotten water on my GEM module. Does your tranny fluid smell burnt or is it NOT Pink or a rich red color? If it is, you may have more problems.

You have a 2001 which has the "mechanical diode" which is basically a one way clutch that usually slips between several gears not just O/D so I don't think that is your problem.

I'm sure Marc will be on later, and hopefully he can shed more light on the situation. If all of your other gears are working fine I don't think your whole trannies shot, but hey I'm not the ford mechanic... Marc is

[Urayo]

No burn smell on the tranny fluid and is still rich red , the tranny shifts ok the other gears except for the last gear or O/D. By the way what is the GEM module stands for and were is located ? I checked the overdrive switch and looks good for me. Also that’s interesting what you told me there about “mechanical diode” , since new she always used to slip the fourth gear or O/D but just very slightly.

[mschn99]

well, honestly this could be a torque converter failing, but the first thing i would like to know is the codes, and we will go from there...

[Urayo]

I will get her scan tomorrow I will post here the results codes. Thanks guys for the help.

[Maintain]

Don't worry about it being your GEM module, when that starts going things like door locks, key fob, lights, and O/D light start acting quirky...

[Urayo]

Hi guys, I got her scan today and got the followings codes: P0741 Torque Converter Clutch Circuit Performance or Stuck Off , P0745 Pressure Control Solenoid Malfunction. The guy that scan her who is a tranny repair tech. he told me that I need to replace the solenoid bank, he also told me that my tranny (4R100) ford did a revision, he showed me a tech. manual of the tranny and told me about the modifications that has to be done if the tranny has to be overhauled. What do you guys think ?

[Urayo]

Doing some research I found this in the dieselmann's page.

2001-2002 Trucks with 4R100 Torque Converter Clutch Solenoid Codes:
Some trucks build between 1-1-01 to 5-1-02 may exhibit a flashing OD light and possibly harsh shifting, with any or all of the following trouble codes: P0740, P0741, P0743, P1744. This may be due to high resistance in the torque converter clutch solenoid, which results in lower torque converter lock pressures. The transmission solenoid body should be replace with P/N F81Z-7G391-CB to correct. Broadcast Message 3559

Probably I should give it a shot to replace the solenoid body, it doesn’t look so hard to change. Have you guys change this before ?