Preventive measures for 2014 6L80 Gearbox

[movario]

Hi

 

I've read some horrorstories about the torque converter failing and filling the transmission with metal flakes. As I really don't want that to happen, I'm thinking about replacing the torque converter before it fails. My truck has currently around 115k miles. When I changed the transmission oil and filter at 100k, everything looked fine and I have currently no reason to think it will fail soon.

 

1. Is it really that common that the converter fails?

2. Should I go for an OEM Converter? Or any other brand?

3. Where can I get stuff like tightening torques, and technical information?

 

I'm a mechanic, so replacing it shouldn't be a problem.

 

It's a 2014 5.3

[newdude]

Change the fluid every 30k on GM Dexron 6.  If you use something full synthetic like Amsoil, you could probably go 45k.   

 

If you have a good scanner, try reading converter slip rate.

 

 

If you notice any funky driveability, check the slip %.  The faster you can catch it before it starts hitting that 0-100rpm erratic, the less chance of internal damage from converter failure.   

 

Below is for the 6L80/90

 

Quote

 

TCC SLIP CONTROL TEST RESULT	TCC rpm slip peak to peak (at steady throttle)	ACTION	Note
Normal (Callout 1)	Below 20 rpm.	Do nothing.
Damaged (Callout 2)	Near 0 to 100 rpm - erratic.	Inspect transmission further	Inspect transmission pan magnet for excessive metal accumulation.
Degraded (Callout 3)	Near 60 rpm - repeating.	Flush transmission fluid. Refer to bulletin 20-NA-142.	Shudder, surge, fish bite likely.

 

#PIP5504F: Diagnosing Fishbite Chuggle Misfire Feeling Or Shudder Vibration, With A Light Tip In - (Jul 10, 2020)

In general if there is insufficient engine firing pulse isolation or combustion instability, vibrations can be transmitted to the driver typically through the steering wheel, seat track, or accelerator pedal.

1. Fishbite: (also called Surge, nudge, jerk and bump) is a jerk or bump which may be transmitted through the Torque Converter Clutch due to insufficient damping or TCC locking and releasing.  
2. Chuggle: (often called boom) is induced from engine combustion exciting the driveline due to insufficient isolation. Frequency of the boom is affected by driveline mass, stiffness, damping, and gear.
3. Misfire: or knock is the engine having an irregular combustion event.
4. AFM Disturbances can be mislabeled as any of the definitions above as well as shudder below, but in fact has to do with the imbalance caused by less cylinders firing.
5. Torque Converter Shudder/Vibration: Any vibration induced by the torque converter clutch in normal driving mode (with an expected TCC slip amount).  (Most often due to TCC friction material/ATF degradation)

Important: DEXRON 6 is the only approved ATF to be used with 6L (MYA, MYB, MYC, MYD) transmissions at this time.

Diagnosis/Test Instructions:

• Verify and correct any DTC’s prior to proceeding with next steps.
• The use of the PICO scope and NVH software should be used to confirm the Disturbance Frequency and allow the user to see if the disturbance tracks to engine speed (Chuggle, Misfire), road speed (Tire Vibrations), or remains constant across various inputs (TCC Shudder). Place the PICO Scope pick up on a metallic component where vibration can be felt the most (seat track, steering wheel column, accelerator pedal, etc).

  a. - Evaluate within customer complaint range (note if concern occurs in V4 or V8 mode).

  b. - Evaluate at Idle (Warm & Cold Start).

  c. - Evaluate in multiple gears.

• A smooth road is desirable for evaluations to isolate concerns without introducing road inputs/noise.
• Minimize extraneous vibration input by testing on a smooth road and correct any other known vehicle vibration issues (tires, brakes, etc.) before conducting test.
  1. Fishbite – Condition can be best isolated by placing the transmission in manual range 5th gear to turn off V4 mode and monitoring TCC Slip in GDS2.  With engine speed between 1,000 – 1,600 rpm and engine load up to 320 Nm the calibration target is 20 rpm of TCC slip in V8 mode. Under these conditions, slip should not be less than 5 rpm with steady throttle input.  

     Note: ( At 400Nm engine load, the calibration target is 5 rpm of TCC slip.)

  2. Chuggle – Condition can be best isolated in Manual 5th gear while in V8 mode, greater than 320 Nm of engine torque, and engine speeds between 1,200–1,300 rpm when tipping into throttle to load the engine. Can be confirmed by using GDS2 to Command TCC on - condition should be the same with TCC locked. This can be Engine 1st Order Vibration on the PICO Scope as well.
  3. Misfire – Can be viewed in GDS2 under engine control module and then selecting misfire data. This will prompt a screen that will show misfire by each cylinder if the tab Diagnostic Data Display is clicked. This can be Engine 1st Order Vibration on the PICO Scope as well.
  4. AFM Disturbances – While monitoring the Driver Information Center to display V4 or V8 mode, determine if the disturbance only occurs in V4 mode or during the transition between V8 and V4 mode.
  5. Torque Converter Shudder/Vibration – Condition can be best isolated with transmission temperature between 40°C (104°F) - 89°C (192°F). Drive the vehicle in 6th gear, V8 mode, with a transmission input speed of 1,000–1,500 rpms (approximately 64-89 km/h (40–55 mph)), constant throttle input, and engine torque 250-375 Nm.

Important: For some road conditions, it may be required to apply the brake pedal and throttle simultaneously to stay within desired engine torque range.

Press and hold the tow-haul mode button for 5 seconds to disable grade braking to prevent downshifts during test.

Run the test in 3 operational modes:

• Normal Operation (TEHCM commanding TCC apply. Use GDS2 for viewing only).
• GDS2 Commanding TCC in Disabled Operation. (No TCC Apply).
• GDS2 Commanding TCC in Enabled Operation. (TCC Locked).

To confirm TCC Shudder, the vibration concern must be present in normal operation (Mode A), but not present with the torque converter clutch disabled (Mode B) or with the torque converter clutch locked (Mode C).

If the concern is not present in Mode A, then the vibration concern is NOT TCC Shudder.

If the concern is still present with the torque converter clutch disabled (Mode B) or with the torque converter clutch locked (Mode C), the root cause of vibration is NOT TCC shudder.

 

#20-NA-142: Shudder/Surging While Driving - (Feb 9, 2021)

Some customers may comment that a surging condition is felt when driving. Some technicians may find during diagnosis or performing PIP5504F, may identify the surging as a torque converter shudder.
Cause	This condition may be caused by additives in the transmission fluid may have been depleted during vehicle operation. Some of these additives assisted with regulating a consistent slip rate of the clutches.
Correction	Raise the vehicle. Remove the transmission pan.     If metallic debris is present (similar to graphic above), remove transmission and replace the torque converter and replace the transmission filter. Refer to Torque Converter Replacement in SI. If metallic debris is not present drain and clean the oil pan and reinstall transmission oil pan. Fill the transmission with 6 quarts of DEXRON VI Transmission Fluid following published Service Information. Lower the vehicle to a safe level on the hoist and operate the transmission through all 6 gear forward ranges, reverse and neutral. Remove transmission oil pan and drain, reinstall the oil pan. Fill the transmission with 6 quarts of DEXRON VI Transmission Fluid following published Service Information. Lower the vehicle to a safe level on the hoist and operate the transmission through all 6 gear forward ranges, reverse and neutral. Remove transmission oil pan and drain, clean pan and replace the transmission filter. Fill the transmission with 6 quarts of DEXRON VI Transmission Fluid. Set the fluid level following published Service Information.

 

 

Edited April 16, 2021 by newdude

[boettcher40]

I've seen a lot of people recommending and using the OEM ZL1 TC, compared to going circle D. Not sure if that's just do to price?

 

I'm at 130k on a 6spd. Dropped the pan at 100k and swapped filter/fluid. Hoping I'm one of the lucky ones.

[CamGTP]

A tune will help converter life too. I disable the converter in tunes so it's only active in gears 5 and 6.

[swathdiver]

14 hours ago, movario said:

Hi

 

I've read some horrorstories about the torque converter failing and filling the transmission with metal flakes. As I really don't want that to happen, I'm thinking about replacing the torque converter before it fails. My truck has currently around 115k miles. When I changed the transmission oil and filter at 100k, everything looked fine and I have currently no reason to think it will fail soon.

 

1. Is it really that common that the converter fails?

2. Should I go for an OEM Converter? Or any other brand?

3. Where can I get stuff like tightening torques, and technical information?

 

I'm a mechanic, so replacing it shouldn't be a problem.

 

It's a 2014 5.3

It's not very common but more common in your generation truck.  I would "flip the pill" which disables the thermostat in the transmission.  Send in an oil sample to Blackstone Labs for analysis.  I did, said my trans was fine but the fluid at 36k had 10K miles of life left in it.  

 

Oh, check Sonnax's website for all of the latest improvements they offer and why, especially on the converter.  I bought the 6L80 shop manual off of Amazon and Art Landeck's 6L80E shop notes booklet too.

Edited April 17, 2021 by swathdiver

[movario]

Thanks so far.

 

As I have now more free time on my hand, I want to replace the TC.

 

Anyone know "TC Remanufacturing" Torque Converters?

For Sonnax, anyone know someone who sells converters with these kits?

 

Someone in a FB group (and boettcher40 here) mentioned " 2014 Cts V/ZL1 converter bolt right up and don’t seem to have the same issues".

Anyone know more about that?

Edited August 26, 2021 by movario

[Grumpy Bear]

There are three videos in this series from Southern Illinois University

 

 

[pokismoki]

try using the 6 bolt style converter for the 6L90E  2500 trucks with 6.0 used this one