Problem with my Transmission, O/D light blinking. CODE P0741

[jass_BH]

Hi all

Im having a hard time figuring out whats wrong with my transmission. I have a 2003 MM with 4r75w swap. It was rebuilt recently from an experienced local transmission builder. And i installed a 3400 yank torque converter

http://uploads.tapatalk-cdn.com/20160415/77efb9589bf671a30faf698de3fe22 7b.jpg

The problem started when i swapped the trans to 4r75w. The O/D light will blink continuously after 10 minutes of driving.

https://vimeo.com/162969700

And when i check the DTC it shows code P0741.

http://uploads.tapatalk-cdn.com/20160415/b89c84dac9a57716e214cde5c13a3a df.jpg

I searched the DTC and the main cause of this DTC is a bad TCC solenoid or the black connector.

I've changed the transmission black connector and the TCC solenoid.
http://uploads.tapatalk-cdn.com/20160415/2d88d8943ab223d9b5ae718909b9ee 54.jpg

http://uploads.tapatalk-cdn.com/20160415/2fd4ee2eb8897910f3979882f93f7e d2.jpg (photo from the internet, couldn't find my old solenoid).

The transmission worked fine for 3 days after changing the cable and solenoid. Then again same problem happened.

What could be the problem? what can i do?
Please i need your inputs with this regard as i had enough from this issue.


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[fastblackmerc]

Maybe member 88grandmarq will see this an tell you what is wrong.

[Hooptie]

While no transmission expert, I suspect it's in the pcm code.

[Mr. Man]

Are there differences between the 2 transmissions that need to be accounted for in the tune?

[jass_BH]

While no transmission expert, I suspect it's in the pcm code.



The Code will not switch on the check engine light but it will be in bending codes

[jass_BH]

Are there differences between the 2 transmissions that need to be accounted for in the tune?



As far as I know you need only to change The number of holes in the OSS

[Seneca]

Is the Yank convertor a lock up unit?

[jass_BH]

Is the Yank convertor a lock up unit?



Not sure I bought it used from a guy that was running it on a Marauder

Its part number:SS3400/4R70W

I tried to look for it online and couldn't find anything about it

[jass_BH]

So no one is having any idea on what is wrong with my transmission ?!!


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[fastblackmerc]

PM member 88grandmarq - resident transmission expert.

[88grandmarq]

assuming you replace the TCC solenoid with a new or known working one, and you have verified proper voltage to the solenoid from the PCM. its possible the bypass clutch control valve or bore in the valve body is worn.

Sonnax makes an oversized valve, but it requires you ream the bore in the valve body. This is a good option if you are a transmission builder, since the reaming tool is expensive. In your case, I would replace the valve body with a known good valve body.

http://www.sonnax.com/parts/2403-oversized-bypass-clutch-control-valve

[jass_BH]

assuming you replace the TCC solenoid with a new or known working one, and you have verified proper voltage to the solenoid from the PCM. its possible the bypass clutch control valve or bore in the valve body is worn.

Sonnax makes an oversized valve, but it requires you ream the bore in the valve body. This is a good option if you are a transmission builder, since the reaming tool is expensive. In your case, I would replace the valve body with a known good valve body.

http://www.sonnax.com/parts/2403-oversized-bypass-clutch-control-valve



The valve body was changed twice and same thing

The mechanic in our shop is suspecting that the Torque Converter went bad.

We are going to change it with the stock one and see what happens.

Ill keep you posted.

[88grandmarq]

The valve body was changed twice and same thing

The mechanic in our shop is suspecting that the Torque Converter went bad.

We are going to change it with the stock one and see what happens.

Ill keep you posted.

In that case, I would replace the torque converter. I recommend circle D or precision industries.

[fastblackmerc]

The valve body was changed twice and same thing

The mechanic in our shop is suspecting that the Torque Converter went bad.

We are going to change it with the stock one and see what happens.

Ill keep you posted.

Did they use "good" valve bodies?

[jass_BH]

Just to let you guys know that the problem was from the TC ☹️


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[Ourobos]

Thanks for the follow up. Was it a mechanical failure inside the converter?

[jass_BH]

Thanks for the follow up. Was it a mechanical failure inside the converter?



I did not open it, i just replaced it with a stock one and the blinking is gone. So i guess there is something inside it is gone bad


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[crownvic97]

Congrats on getting it figured out at least