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newdude

16-NA-175 8 Speed Shudder UPDATE

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Not sure if this has made rounds on this forum yet, but it was brought to my attention at work as we have a 2016 5.3/A8 in for this concern right now (we've done them in the past but its been a month or two). 

 

I've highlighted in red the big change, GM is no longer replacing converters based on their findings on returned warranty units as it can still come right back.  The triple flush has been dropped for now, just a flush and re-evaluate.  It does appear they must be on to something that is a better fix as they are working on one to be released Q1 2019.  Looks like they will continue to only flush/fill them for now. 

 

This does apply to ALL 8 speed applications, both 8L45 and 8L90, EXCLUDING the new T1 1500 trucks.  Stay tuned...

 

Quote

 

#16-NA-175: Shake and/or Shudder During Light Throttle Acceleration Between 25 and 80 MPH (40 and 128 KM/H) at a Steady State - (Oct 11, 2018)

 

Some customers may comment on any of the following conditions:

 

  • A shake and/or shudder during light throttle acceleration between 25 and 80 mph (40 and 128 km/h) steady state driving when transmission is not actively shifting gears.
  • A shudder feeling that may be described as driving over rumble strips or rough pavement.
  • Shudder feeling is evident in both Drive and M7 MY15-16 & L7 MY17, MY18 and MY19 mode.

 

Important: Do NOT replace the torque converter or transmission assembly for this condition. Engineer reviews have proven that replacing the torque converter does not provide a long-term solution to TCC shudder. A revised service procedure will be released in Q1 of 2019. If the vehicle experiences a repeat shudder condition, this document should be followed again.

 

All part replacement claims will be subject to engineering analysis. Any part(s) determined not to be defective will be subject to a possible claim debit.

 

Note: This procedure has been updated to eliminate the replacement of the transmission oil filter.

 

To confirm TCC Shudder, the vibration concern must be created in normal operation (Mode A) of the test. If the concern is gone with the torque converter clutch disabled (Mode B, TCC Open) and is gone with torque converter clutch enabled (Mode C, TCC Locked), then the vibration root cause is TCC Shudder, and the fluid flush procedure corrective action described below should be performed.

 

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 enabled (Mode C, TCC slip speed at zero), then the vibration root cause is NOT TCC Shudder.

 

Vibrations not identified as TCC Shudder should be further investigated using the Vehicle Vibration Diagnosis in SI as a starting point.

Service Procedure
 

Important: Requires Mobil 1 Synthetic LV ATF DEXRON HP transmission fluid.

 

Note: Replacement of the transmission oil filter is not required for this procedure.

 

  1. Drain, Clean pan/magnet, Oil Fill, & Remove fluid from the oil cooler lines.

    Note: If you find that the fluid is cloudy, milky, or appears to be contaminated with water or engine coolant, DO NOT proceed with below steps. Follow Both SI Procedures for Cooling System Leak Testing and Engine Coolant/Water in Transmission.

    • A.) Use filtered compressed air regulated to 60 psi to remove transmission fluid from the transmission oil cooler lines.
    • B.) Remove the transmission fluid pan and drain transmission fluid following SI procedures for the application you’re working on. Discard all oil.
    • C.) Clean the pan/magnet if any metallic particles present.

 

Install the transmission fluid pan and refill with new Mobil 1 Synthetic LV ATF DEXRON HP transmission fluid following the Fluid Fill Procedure in SI to obtain correct fluid level.

 

The shudder should be improved after the completion of this flush procedure.

 

Note: Shudder should improve directionally right away, but for full affect, the vehicle may need to be driven up to 200 miles (322 km) and a minimum of two cold to hot drive cycles before determining if the fluid flush corrected the condition or not. Do not re-evaluate vehicle for additional customer shudder concerns until the vehicle has been driven 200 miles (322 km).

 

 

Edited by newdude

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There is supposedly a new fluid yet to come out. 

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Hmm interesting.  Can anyone give a deeper explanation about what the TCC shudder feels like?

 

The last month my truck has started randomly doing a quick vibration (fast paced vibration like driving over rumble strips on highway) that typically lasts a second or less.  Sometimes it will do it multiple times over a perioid of several seconds, other times its just a quick vibration.  Its a pretty significant vibration, I really can feel it in the steering wheel and the entire column shakes.   Seems like all interior pieces vibrate as well.

 

I'm not able to duplicate the issue. 

 

15 6.2 w/ 8spd and 43k miles.   

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8 hours ago, SkiDooNick700 said:

Hmm interesting.  Can anyone give a deeper explanation about what the TCC shudder feels like?

 

The last month my truck has started randomly doing a quick vibration (fast paced vibration like driving over rumble strips on highway) that typically lasts a second or less.  Sometimes it will do it multiple times over a perioid of several seconds, other times its just a quick vibration.  Its a pretty significant vibration, I really can feel it in the steering wheel and the entire column shakes.   Seems like all interior pieces vibrate as well.

 

I'm not able to duplicate the issue. 

 

15 6.2 w/ 8spd and 43k miles.   

 

basically it feels like the transmission is slipping to me. if you watch the rpms, it would jump a few hundred rpm and you'd get the vibration. Happened between 1100-1600 rpm roughly. IF I drove it in manual and kept the rpms around 2k, it was fine. I just had my TC replaced and fluid changed to fix it. It worked. but I suspect it shall come back. 

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8 minutes ago, Roscopcoletrain said:

 

basically it feels like the transmission is slipping to me. if you watch the rpms, it would jump a few hundred rpm and you'd get the vibration. Happened between 1100-1600 rpm roughly. IF I drove it in manual and kept the rpms around 2k, it was fine. I just had my TC replaced and fluid changed to fix it. It worked. but I suspect it shall come back. 

I notice my tach bouncing up and down and few hundred rpm however I can't recall if it does it when the vibration happens.  I am able to duplicate the tach jumping around by putting it in Manual and driving around 45mph / 70km.

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8 minutes ago, SkiDooNick700 said:

I notice my tach bouncing up and down and few hundred rpm however I can't recall if it does it when the vibration happens.  I am able to duplicate the tach jumping around by putting it in Manual and driving around 45mph / 70km.

I took a video to show them at the dealer. everytime it would bounce, i'd get the shudder

 

 

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4 minutes ago, Roscopcoletrain said:

I took a video to show them at the dealer. everytime it would bounce, i'd get the shudder

Hmm, maybe mine isn't so much related to the TCC. My tach bounces like yours but no shake in the cab. I just hear the exhaust note changing along with the tach. The other thing I try to pay attention to is to see if its like a bump or expansion joint in the road which is causing the vibration.  I really do not think this is the case though as I've had it happen on smooth asphalt roads.  Thank you for sharing your experience!

 

I'm interested to see what comes of this new fix.

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8 minutes ago, SkiDooNick700 said:

Hmm, maybe mine isn't so much related to the TCC. My tach bounces like yours but no shake in the cab. I just hear the exhaust note changing along with the tach. The other thing I try to pay attention to is to see if its like a bump or expansion joint in the road which is causing the vibration.  I really do not think this is the case though as I've had it happen on smooth asphalt roads.  Thank you for sharing your experience!

 

I'm interested to see what comes of this new fix.

 

Exhaust note change with tach flutter is typically AFM.  The rumble strip feeling is a common symptom of A8 converter shudder. 

Edited by newdude
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22 minutes ago, newdude said:

 

Exhaust note change with tach flutter is typically AFM.  The rumble strip feeling is a common symptom of A8 converter shudder. 

Thank you for the reply.  By the time this new fix comes out I'll be ready for another oil change.  I'll describe the symptoms this way to my service guy and see where it goes from there.

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i just had the flush done at 26k miles for the shudder, my tach did the same thing bouncing slightly when the shudder happened. I may have to email the engineer I dealt with over at GM and see if he can explain some more in detail with what the next fix will be.

 

 

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I took a video to show them at the dealer. everytime it would bounce, i'd get the shudder
 
 
Mine thoes the same thing but its a silverado 1500 2016

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So in this case what should i do....take it to the dealership...its out of warranty with 62000 miles...or wait

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