TCC Shudder and New Mobil 1 Fluid Exchange

A new transmission fluid exchange procedure and a new formula of Mobil 1 Synthetic LV ATF HP transmission fluid have been released to address torque converter clutch (TCC) shudder conditions on 8L45 and 8L90 8-speed automatic transmissions (RPOs M5N, M5T, M5U, M5X) in some 2015-2017 Escalade, Yukon; 2015-2018 Silverado, Sierra; 2015-2019 Corvette; 2016-2018 CT6; 2016-2019 ATS, CTS, Camaro; and 2017-2019 Colorado and Canyon models.

The new fluid exchange procedure requires the use of the DT-45096 TransFlow Cooler Flush Machine and DT-52263 Transmission Fluid Exchange Tool Kit. (Fig. 10) The tool kit began shipping to dealerships at no charge in late January 2019. All GM dealerships should receive the tool kits by the end of March 2019.

Fig. 10


Shudder Test

The new service procedure addresses shake and/or shudder conditions during light throttle acceleration between 25 and 80 MPH (40 and 128 KM/H) at a steady speed when the transmission is not shifting gears. To ensure TCC shudder is diagnosed correctly, drive the vehicle on a smooth road with transmission sump temperature between 122°F (50°C) – 158°F (70°C). Constant throttle input on a smooth grade is needed.

A shudder condition may also be a chuggle, surge or vibration condition. Use GDS 2 or the CH-51450 PicoScope to confirm that the concern is TCC shudder and not a tire/wheel vibration or a driveline vibration, for example. A screen print from GDS 2 or the PicoScope showing the TCC shudder event must be attached to the Repair Order hard copy. (Fig. 11)

If TCC shudder is present, a vibration peak will appear within +/- 2 Hz of the frequency listed in Bulletin #18-NA-355. Refer to the bulletin for additional information, including required shudder test conditions for each vehicle being diagnosed as well as the fluid exchange procedures.

Fig. 11


Fluid Exchange

The TCC shudder condition is related to moisture content in the transmission fluid. The current fluid tends to be hydroscopic, or absorbs moisture, which increases the chance of TCC shudder. There are three different fluid exchange procedures to follow, depending on vehicle application, so that an acceptable concentration of the new HP fluid is achieved in the transmission.

The new Mobil 1 Synthetic LV ATF HP transmission fluid is now available to U.S. dealerships through your local GM Oil Distributor. The new Mobil 1 Synthetic LV ATF HP transmission fluid is available in quart bottles (GM Part Number 19417577) and, for a limited time, in 55-gallon drums (GM Part Number 19417904) (Fig. 12) in most locations. Drum production ended in January 2019. The GM part numbers are not on the product. The Mobil 1 Synthetic LV ATF HP fluid and the required tool kit will be available to all Canadian dealerships by the end of March 2019. GM Part Numbers for 0.946 liter bottles will be provided at that time.

Fig. 12


TIP: Mobil 1 Synthetic LV ATF HP transmission fluid is required for all 8-speed transmission repairs regardless of the repair being completed.

Quart bottles, which can be identified by a new blue banner across the front of the bottle (Fig. 13), will be limited to 20 cases/120 quarts per dealer per week during the initial launch of the new product. The new bottles also feature the HP license number J-62120 on the back label. The use of the black label Mobil 1 Synthetic LV ATF HP fluid (GM Part Number 19355656) should be discontinued.



Fig. 13


For a video demonstration of the new fluid exchange procedure, check out the December 2018 Emerging Issues Broadcast, course number 10218.12V, available through the Center of Learning. In Canada, refer to the January 2019 TAC Talk seminar.


– Thanks to Mark Gordon


Updated March 15, 2019

All-New 2019 Blazer Arrives with Attitude
RKE Transmitter Pocket Locations on the New Silverado and Sierra


  1. The old HP formula can be mixed with the new HP formula when completing repairs such as valve bodies, speed sensors etc. There’s not issue when intermixing the two fluids.

  2. Martin cook says:

    Can this new oil be mixed with the oil say in a filter change on a truck that did not have a convertor shudder but is just having a trans service.

  3. martin cook says:

    I have to agree with Jason Glover on this you only make the customer come back so many time and then they don’t come back at all, and as for the snap shot of the shudder that’s just a way for gm to charge it back to the dealership if its not done to what they like to see, anyone that’s been working on transmissions for any amount of time know what a convertor shudder is.

  4. The Mobil 1 Synthetic LV ATF HP transmission should only be used in the 8L45 and 8L90 Automatic Transmissions. Reference the Service Information for the appropriate fluid for all other transmission applications.

  5. Michael DiPasquale says:

    Can this fluid be used in the 6 speed trannys that have a similar fish bite / chuggle / shudder at light throttle input?

  6. gary dickens says:

    hey Jason I agree we made more on the old flush BUT be aware the majority of the flush work was not getting done properly. or not at all because of the popular belief that this wasn’t going to fix it. – I actually got in trouble for flushing instead of replacing before all this broke loose -I think the time is good to do the flush but they need to add for documentation and have someone else drive with you so you don’t hit the wall trying to get a snap shot the thing with getting a fix and here is a good honest take on it you need to drive the vehicle after and verify its fixed if not you need to clock in go out and get the pico and the gds data upload it to tac after putting additional 200 miles on it” make you manager drive it for a week” , they will approve replacement if necessary. I have done 4 -55gallon drums and only 1 came back and did get a new converter there is a redesigned converter for the 45 series like the Colorado and ct6. if you go into the si forums you will find a lot of information and people willing to help.

  7. Marshal, your dealership has the correct fluid. The product code and license number are correct.

  8. I’m confused on this new fluid and need some help.
    Seems like no one knows what transmission fluid I have in a 55 gallon drum received back in January as to whether its the new blue label or old lack label Mobil 1 LV HP ATF synthetic fluid

    label on the barrel says
    packaged by 10118L18A
    product code 124714
    Batch# 70284914
    License# J6220
    Its a grey barrel with blue print
    small bar label # 1247148000
    Large bar label# 101002084131
    I believe our parts manager has contacted someone but with no confirmed info.
    This information is vital to me being 1 OF 2 trans builder for GM dealerships in the Permian Basin area.
    I want to thank you in advance for your assistance in this matter.

  9. Dealers should discontinue the use of the black label Mobil 1 Synthetic LV ATF HP fluid. A communication from CCA will be released soon advising dealers of how to dispose of the old product.

    The base stock of old fluid (19355656) has the ability to attract low levels of moisture, which can cause degradation of the coefficient of friction of the fluid. The new fluid (19417577) has a new GTL (Gas to Liquid) base stock that is able to tolerate more moisture. Shuddering transmissions and torque converters have been recovered with the new fluid. New transmission fluid tests have been developed due this issue to prevent it from occurring with new transmission fluids.

  10. Our parts department contacted the local Mobil 1 rep because we are stuck with quite a lot of the black label fluid. the Mobil 1 rep told him that there is no difference between the black label product and the blue label product. Is this true?

  11. It is not recommended to use any aftermarket fluid exchange machines. The procedure in TSB #18-NA-355 provides a new fluid concentration level of 93% or higher. Some aftermarket fluid exchange machines may not provide an acceptable concentration level of new fluid in the transmission.

  12. Can you use another transmission flush machine.

  13. The shudder condition experienced on the 8-speed transmission in most cases is torque converter clutch (TCC) shudder. However, in some cases, the shudder, fish bite, chuggle, surge or vibration is caused by something other than the torque converter clutch. That is why TSB #18-NA-355 is requesting a screen print of either a GDS2 Session showing TCC slip, GDS Special Functions showing TCC Locked, or a PicoScope screen print showing TCC shudder (vibration frequency). Duplication of a customer condition can vary from vehicle to vehicle and can also be influenced by environmental conditions. If you are experiencing difficulty in duplicating the shudder in the time allowed within TSB #18-NA-354, other labor hours (OLH) should be utilized and documented accordingly.

  14. Jason Glover says:

    Just curious as to why we are required to provide documentation for the tcc shudder. This concern is not new and after all this time messing around with the old fluid (which I also received better pay for) I’m pretty sure every technician involved in this knows what the shudder feels like. My problem is that I have a customer with a CT6 that has been in 3 times for a tcc shudder. We replaced the fluid twice and the third time advised him that the permanent repair was coming in February. It’s also cold here in ohio now so I’m likely to feel that the shudder is probably not happening at the moment. If we call this customer and say the fix is out but if your car isn’t currently shuddering sorry about your luck. Come back a fourth time and we’ll take care of it. How do you think that’s going to go over? I guarantee if we do it as customer enthusiasm the claim will get rejected and we don’t currently have a DMA to approve it. Just a frustrating situation after all this time. This is just one example as we have several of these customers under this situation. Thanks for your time.