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Took my car in for warranty work and had them check an intermittent check engine light. They came back after a few hours investigating and said the torque converter is going bad, and recommended replacing it at a cost of $1500 parts and labor. Anyone else had a similar issue? Is it worth replacing with OEM parts at a dealer or can a transmission shop or similar replace it with an improved part from an aftermarket source?

Details: 2012 3.6L SXT.
58,000mi, I usually drive <10miles a day, but currently due to work environment, driving 40+ Highway miles a day. I don’t think I notice any difference in the way it drives....planning on keeping the car for 3-4 more years.
 

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The Pork Wagon (‘14 Cop Charger)
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Took my car in for warranty work and had them check an intermittent check engine light. They came back after a few hours investigating and said the torque converter is going bad, and recommended replacing it at a cost of $1500 parts and labor. Anyone else had a similar issue? Is it worth replacing with OEM parts at a dealer or can a transmission shop or similar replace it with an improved part from an aftermarket source?

Details: 2012 3.6L SXT.
58,000mi, I usually drive <10miles a day, but currently due to work environment, driving 40+ Highway miles a day. I don’t think I notice any difference in the way it drives....planning on keeping the car for 3-4 more years.
Torque converter failure on that transmission is uncommon, and unless you experienced some sort of drivability issues previously, I would say it is unlikely the torque converter has failed with no symptoms line this.

Did they give you a printout if what the DTCs were that illuminated the CEL? Any other info about what is wrong, causes, etc?

Ask them how many torque converters that have seen go out on the NAG1 transmission (what yours is), I’d be curious to hear their reply. (If it’s anything more than 1 or 2, they are full of it).
 

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I'd agree that T/C failure is a pretty unusual failure but is entirely possible. I'd see like what faults you had though, if there were any TC clutch related DTCs.

And yes a generic trans shop can likely install a rebuilt or replacement unit for a lot less $.
 

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Thanks for the inputs, here’s what the printout says:

TCM P0741 Torque Converter Clutch Circuit Performance
Code found to have sporadic errors when in Fifth gear due to slip of the converter when under load.
Recommend replacing torque converter or transmission to bring vehicle back to normal operation at high gear loads.

Any insights or advice would be greatly appreciated.
 

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The Pork Wagon (‘14 Cop Charger)
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Thanks for the inputs, here’s what the printout says:

TCM P0741 Torque Converter Clutch Circuit Performance
Code found to have sporadic errors when in Fifth gear due to slip of the converter when under load.
Recommend replacing torque converter or transmission to bring vehicle back to normal operation at high gear loads.

Any insights or advice would be greatly appreciated.
Your transmission is the venerable NAG1, a Mercedes Benz workhorse also known as the 722.6 for Mercedes applications. It was installed in many, many Mercedes Benz vehicles from the late 90s Into the early 2000s, and then FCA started putting it in their cars up through 2014 year models.

Needless to say, there is a lot of those transmissions out there, and there is a considerable amount of data on what is most likely to become a problem on them. I have read through much of that data, and if there is one thing I cannot remember seeing a report of, it’s a bad torque converter.

Yours may have a bad torque converter, but if it does, it will be the first one I have heard about with such a failure.

In my humble opinion, I think it is much more likely that your trans needs either a new conductor plate or wiring plug connector, or both. There are countless examples of those transmissions having various, seemingly unrelated problems, and the cause turned out to be fluid intrusion into or onto the two parts mention above.

Now obviously I cannot say for sure that is your problem’s cause, but with a repair bill of $1500 staring me in the face, I would rather try replacing the conductor plate and case plug first to see if that did the trick. Their cost if ordered off Amazon is around $200, and they are not terribly difficult to install in one’s garage. Even if someone were paid to do the job, I can’t see the bill being more than $500.

If you do go with the converter replacement, I would make sure to get in writing that if any further transmission issues occur immediately after this, the torque converter parts and work is either credited or refunded toward further trans diagnosis and labor.

Telling you your torque converter is bad based upon the presence of a single TCM code reeks of parts shotgunning to me, and it displays a lack of interest in truly resolving customer’s problems. Some places would much rather extract as money as possible than fix the issue the first time. I hope this place you took it to isn’t one of them.
 
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Diagnostics for the P0741 fault essentially split into 2 paths - does the converter slip excessively when the TCC is operating in slip mode OR is there another condition affecting TC clutch control that is causing slip difference in slip mode to exceed 60 RPM.

If it is 'truly' slipping then you're looking at a bad converter. But an electrical or mechanical/hydraulic issue causing undesirable TCC system function (excessive slip) can also cause the P0741.

The TCC test procedure is as follows:

1. Operate the vehicle until the transmission sump temperature is to greater than 65° C (150° F).
2. Using the shifter lever, select third gear.
3. Accelerate the vehicle to third gear and hold.
4. With the scan tool, verify the TCC status is reading "SLIP".
5. Monitor TCC Desired Slip and TCC Actual Slip.
6. Operate the vehicle at 30 mph while maintaining third gear.
7. Lightly depress the accelerator and hold the throttle position steady between 40 and 50%.
8. Slowly accelerate vehicle using steady throttle without causing TCC Status to read “OPEN”.

If at any time during the above test the TCC Status changes from SLIP to OPEN, or the vehicle downshifts to a lower gear, the test is invalid and must be performed again.
9. Compare TCC Actual Slip and TCC Desired Slip during steady throttle acceleration with TCC Status continually reading “SLIP”.

Does TCC Actual Slip exceed TCC Desired Slip by more than 60 rpm while accelerating at a steady throttle and staying in SLIP mode?
If Yes:
Inspect transmission fluid for water contamination.
Inspect internal transmission. Pay particular attention to the components related to the TCC such as possible missing Input Shaft Seal Ring, Lockup Control Valve sticking in its bore, and/or a leaking TCC Solenoid. If no internal transmission issues found, replace the Torque Converter.

If No:
1. Using the schematics as a guide, check the Transmission Control Module (TCM) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for Service Bulletins for any possible causes that may apply. If no problems are found, replace and program the TCM in accordance with the Service Information.
2. Perform TCC slip test to verify repair.

NOTE: To set P0741 fault, TCM must encounter three events where the TCM cannot control TCC Actual Slip to TCC Desired Slip in a single key cycle.

Hope this helps.
 

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The Pork Wagon (‘14 Cop Charger)
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6,513 Posts
Diagnostics for the P0741 fault essentially split into 2 paths - does the converter slip excessively when the TCC is operating in slip mode OR is there another condition affecting TC clutch control that is causing slip difference in slip mode to exceed 60 RPM.

If it is 'truly' slipping then you're looking at a bad converter. But an electrical or mechanical/hydraulic issue causing undesirable TCC system function (excessive slip) can also cause the P0741.

The TCC test procedure is as follows:

1. Operate the vehicle until the transmission sump temperature is to greater than 65° C (150° F).
2. Using the shifter lever, select third gear.
3. Accelerate the vehicle to third gear and hold.
4. With the scan tool, verify the TCC status is reading "SLIP".
5. Monitor TCC Desired Slip and TCC Actual Slip.
6. Operate the vehicle at 30 mph while maintaining third gear.
7. Lightly depress the accelerator and hold the throttle position steady between 40 and 50%.
8. Slowly accelerate vehicle using steady throttle without causing TCC Status to read “OPEN”.

If at any time during the above test the TCC Status changes from SLIP to OPEN, or the vehicle downshifts to a lower gear, the test is invalid and must be performed again.
9. Compare TCC Actual Slip and TCC Desired Slip during steady throttle acceleration with TCC Status continually reading “SLIP”.

Does TCC Actual Slip exceed TCC Desired Slip by more than 60 rpm while accelerating at a steady throttle and staying in SLIP mode?
If Yes:
Inspect transmission fluid for water contamination.
Inspect internal transmission. Pay particular attention to the components related to the TCC such as possible missing Input Shaft Seal Ring, Lockup Control Valve sticking in its bore, and/or a leaking TCC Solenoid. If no internal transmission issues found, replace the Torque Converter.

If No:
1. Using the schematics as a guide, check the Transmission Control Module (TCM) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for Service Bulletins for any possible causes that may apply. If no problems are found, replace and program the TCM in accordance with the Service Information.
2. Perform TCC slip test to verify repair.

NOTE: To set P0741 fault, TCM must encounter three events where the TCM cannot control TCC Actual Slip to TCC Desired Slip in a single key cycle.

Hope this helps.
Where would one acquire a scanner tool that has the ability to read the TCM/TCC status?

None of the 3 different models of DiabloSport tuner I’ve had could access the TCM and read TCC status.

My TranZformer isn’t even that robust, and it hooks straight into the TCM wiring itself.

I’m assuming dealership service departments have such a tool, but do they sell them in the aftermarket for the general public?
 

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That I don't know, the diag procedure assumes you have access to the wiTech platform. But if you're ever in the north cities lmk ;)
 
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