Shake and/or Shudder During Light Throttle Acceleration Between 25 and 80 MPH (40 and 128 KM/H) at Steady Speed – 2019 Chevrolet Silverado & GMC Sierra 1500

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Service Bulletin Bulletin No.: 19-NA-121
Date: June, 2019
TECHNICAL
Subject: Shake and/or Shudder During Light Throttle Acceleration Between 25 and 80 MPH
(40 and 128 KM/H) at Steady Speed
Attention: This Bulletin only applies to vehicles sold in the U.S., Canada and Middle East.
Brand: Model:
Model Year: Date Breakpoint:
Engine: Transmission:
from to from to
Chevrolet Silverado 1500
(New Model)
2019 2019 SOP March 01,
2019 L3B, L84 MQE
GMC Sierra 1500
(New Model)
Involved Region or Country United States, Canada, Chile, Thailand and Middle East Operations (MEO)
Condition
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 modes.
Diagnosis Instructions
To ensure torque converter clutch (TCC) shudder is
diagnosed correctly, please drive the following
schedule on a smooth road with transmission sump
temperature between 50°C (122°F) – 70°C (158°F).
Important: For some road conditions, it may be
required to apply the brake pedal and throttle
simultaneously to stay within desired gear, engine firing
mode, engine torque range, and engine/vehicle speed
ranges.
Press and hold the tow-haul mode button for 5 seconds
to disable grade braking to prevent downshifts
during test.
Run the following tests for 3 operational modes:
A. Normal Operation (GDS2 for viewing only)
B. GDS2 Commanding TCC in Disabled Operation
(TCC Open)
C. GDS2 Commanding TCC in Enabled Operation
(TCC Locked)
Shudder Test
Refer to the table below for conditions pertaining to
specific applications. In each vehicle, constant throttle
input on a smooth grade is desirable.
Vehicle Information Shudder Test Conditions
Make Application: Engine
Type
Engine
RPO
Trans
RPO Gear
Engine
Mode (4,
V6, V8)
Transmission
Input
Speed (rpm)
Vehicle
Speed
mph
(km/h)
Engine
Torque
(Nm)
Chevrolet/
GMC
Silverado/
Sierra
4 CYL.
Turbo L3B MQE 4 4 1100-1500 45-55
(72-88) 100–250
Chevrolet/
GMC
Silverado/
Sierra
8
CYL.
NA
L84 MQE 8 V8 1050-1500 45-55
(72-88) 200-375
Page 2 June, 2019 Bulletin No.: 19-NA-121
GDS Test
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.
GDS can be used to monitor TCC Slip to confirm TCC
Shudder. Once TCC shudder is duplicated TCC slip
speed should be monitored while driving at a steady
speed and steady throttle. TCC shudder typically will
present itself in a saw tooth or oscilloscope pattern
where TCC slip will increase and decrease rapidly. The
increase may be as much as a 150 rpm and decline to
below 0 rpm, creating a saw tooth or oscilloscope type
pattern. When TCC slip speed is graphed on the GDS
screen. Desirable slip speed would present itself with 5
to 15 rpm variation. Slip speed will vary by application.
The slip speed is it should be consistent and not erratic
or presented in a saw tooth or oscilloscope pattern
Vibrations not identified as TCC shudder should be
further investigated using the Vehicle Vibration
Diagnosis in SI as a starting point.
5343327
Bulletin No.: 19-NA-121 June, 2019 Page 3
This is an example of TCC slip speed on a 5.3 (L84)
truck. Note the improvement in slip speed after
immediately after the fluid exchange procedure. The
slip speed will improve after additional mileage is
accumulated. This improvement will occur over the
course of 200 miles (320 km) and a minimum of two
cold to operating temperature drive cycles. The truck
should be returned to the customer for the mileage
accumulation.
5336317
Example of GDS Screen Print.
Important: Obtain a single page screen print from
GDS that shows the TCC shudder event. This screen
print must be attached to the Repair Order hard copy
for reference. A screen print can be completed by
pressing the Print Screen button on your laptop
computer or by using a program or application such as
Snipping Tool.
Examples of acceptable screen prints:
• GDS2 Session showing TCC slip
• GDS2 Special Functions showing TCC Locked
Slip Speed
Special Tools
DT-52263 Transmission Fluid Exchange Kit:
• DT-52263-1 Block Assembly (includes fluid drain
hose, spring clamp)
• DT-52263-5 Radiator Cooler Drain Adapter
3763203
• DT-51190 Transmission Oil Fill Adapter
Page 4 June, 2019 Bulletin No.: 19-NA-121
5181938
• GE-47716-2 Graduated Bucket
1215917
DT-45096 TransFlow Cooler Flush Machine
4733125
DT-45096-31 TransFlow Adapter (one of two pieces
from DT-45096-30)
Service Procedure
Initial TransFlow Flush Machine Setup
Important: The prepping procedure only needs to be
completed if the DT-45096 supply reservoir has
DEXRON VI fluid in it and has not been converted to
use the new blue label Mobil 1 Synthetic LV ATF HP
fluid.
Note: The prepping procedure only needs to be
completed if HP fluid is not in the supply reservoir.
1. Connect the TransFlow adapter DT-45096-31 to
the supply line of the DT-45096 TransFlow
machine.
5180884
2. Switch the DT-45096 TransFlow to Idle.
3. Connect power leads to the vehicle 12-volt DC
supply.
4. Turn the TransFlow main switch ON.
5. Connect air supply to the DT-45096.
6. Place the TransFlow supply hose with adapter
DT-45096-31 into a waste reservoir using care not
to spill the expelled fluid.
7. Switch the DT-45096 TransFlow to Flow and allow
all the fluid in the supply reservoir to be removed
and placed in the waste reservoir.
8. Switch the control switch back to idle.
Fluid Exchange Procedure – 2019 Chevrolet
Silverado and GMC Sierra (New Body Style)
Equipped with the RPO (MQE)
Important: This procedure must be followed as
published. The exchange process is required to obtain
proper level of new blue label Mobil 1 Synthetic LV ATF
HP fluid. Intermixing of other types of transmission fluid
or aftermarket additive packages will result in a low
concentration level of new fluid and will not provide
satisfactory results.
Bulletin No.: 19-NA-121 June, 2019 Page 5
1. Fill the DT-45096 with 20 quarts of HP fluid.
2. Raise the vehicle on a hoist.
5182541
3. Install the DT-45096-31 TransFlow adapter (1) to
the DT-51190 fluid fill adapter (2).
5180563
4. Remove the transmission oil cooler pipe assembly
from the transmission.
5. Install the DT-52263-1 Adapter Block Assembly
(1), reusing the seal from the transmission oil
cooler pipe assembly.
6. Tighten the bolt (2) to 22Y(16 lb ft).
7. Place the hose (3) in the GE-47716-2 Graduated
Measuring Bucket, utilizing a Spring Clamp to
retain the hose.
3723844
8. Remove the level set plug (1) from the
transmission.
Important: DO NOT over tighten the DT-51190 as it
can be damaged by excessive torque. DO NOTexceed
9Y(80 lb in).
9. Install the DT-51190/DT-45096-31 assembly and
hand tighten as shown in the graphic above.
3723839
10. Connect the TransFlow fluid feed (supply) line (3)
to the DT-45096-31 adapter (2).
11. Lower the vehicle.
Caution: DO NOT REMOVE MORE THAN 3 QUARTS
OF FLUID AS IT COULD CAUSE FLUID PUMP
CAVITATION AND POSSIBLY DAMAGE THE
TRANSMISSION.
12. Utilizing the graduated bucket, start the engine and
run 30 – 45 seconds until 3 quarts of fluid is
expelled.
Page 6 June, 2019 Bulletin No.: 19-NA-121
13. Shut the engine off immediately.
14. Connect the DT-45096 to the vehicle battery
12 volts and connect shop air to the air connection.
5181027
15. Switch the DT-45096 TransFlow to Flow and add
4 quarts of HP to the transmission.
5181020
16. Switch the DT-45096 TransFlow to Idle (Reducing
fluid level in the TransFlow from 20–16).
17. Switch the TransFlow DT-45096 to Flow and start
the engine:
17.1. Add a maximum of 4 quarts of HP Fluid to
the transmission, turn the TransFlow switch
to idle once 4 quarts have been added, while
allowing 4 additional quarts of oil to fill the
DT-graduated bucket (Reducing fluid level in
the TransFlow from 16 – 12).
Note: DO NOTadd additional transmission fluid until
the 4 quarts of oil have been removed from the
transmission (Reducing fluid level in the TransFlow
from 12–8).
17.2. Repeat step 17.1.
17.3. Add a maximum of 5 quarts of HP fluid to the
transmission while allowing 5 additional
quarts of oil to fill the DT-graduated bucket
(Reducing fluid level in the TransFlow
from 8 – 3).
5181401
17.4. Shut the engine off once 16 quarts of fluid
have been collected.
17.5. Properly dispose of the expelled
transmission fluid.
18. Raise the vehicle.
19. Disconnect the DT-45096 TransFlow feed (supply)
line from DT-45096-31 TransFlow adapter.
20. Using care, remove DT-45096-31/DT-51190 as an
assembly.
21. Remove the DT-51190 fluid fill adapter from
DT-45096-31 hose.
22. Install the level set plug.
Tighten
Torque the plug to 9Y(80 lb in).
23. Remove DT-52263-1 Adapter Block Assembly
from the transmission.
Bulletin No.: 19-NA-121 June, 2019 Page 7
24. If equipped, remove the Thermal By-Pass Block
from the cooler pipes (L84 only).
24.1. If equipped with the 4 cylinder (L3B) engine
skip to step 27.
25. Using clean compressed shop air regulated to
50 PSI blow out the transmission oil cooler lines to
remove any remaining transmission fluid.
26. If equipped, install the Thermal By-Pass Block from
the cooler pipes.
27. Install the transmission oil cooler pipe using a new
cooler block seal.
28. Partially lower the vehicle.
29. Start the engine.
30. Using care, shift the transmission through all
forward ranges and Reverse.
31. Shift the transmission into Park.
32. Perform the Transmission Fluid Level and
Condition Check outlined below in this procedure:
32.1. Get the transmission fluid temperature to the
proper temperature.
32.2. Install the level set plug.
Tighten
Torque the plug to 9Y(80 lb in).
The TCC shudder condition should be directional
improved immediately after the fluid exchange
procedure. It may take up to 200 mi (320 km) for the
TCC shudder condition to be eliminated. It is not a
requirement for the dealer to drive the vehicle 200 mi
(320 km). The customer should be advised that the full
effect will take up to 320 km (200 mi) and a minimum of
two cold to operating temperature drive cycles.
Transmission Fluid Level and Condition
Check
This procedure checks both the transmission fluid level,
as well as the condition of the fluid itself. Because the
transmission on this vehicle is not equipped with a fill
tube and dipstick, a tube in the bottom pan is used to
set the fluid level.
Warning: The transmission fluid level must be
checked when the transmission fluid temperature
(TFT) is between 35–45°C (95–113°F). If the TFT is
not within this range, either idle or brake torque the
vehicle to raise the fluid temperature, or shut off the
vehicle to allow the fluid to cool as required. Setting
the fluid level with a TFT outside this range will
result in either an under or over-filled transmission.
TFT>45°C=under-filled, TFT<35°C=over-filled. An
under-filled transmission will cause premature
component wear or damage. An over-filled
transmission will cause fluid to discharge out the
vent tube, possibly causing a fire that may result in
serious bodily injury or severe vehicle damage,
fluid foaming, or pump cavitation.
Note: Silverado and Sierra Models equipped with a
thermal bypass valve, the transmission fluid level
should be checked only after the TFT has reached or
exceeded an operating temperature of 90°C (194°F).
Once the TFT has reached or exceeded 90°C (194°F),
then turn OFF the vehicle and allow the TFT to cool
back down to 35-45°C (95-113°F) before checking the
fluid level as required. Reaching or exceeding an
operating temperature of 90°C (194°F) opens the
bypass valve and allows the cooler to fill up with fluid,
which will result in a more accurate fluid level check.
1. Observe the TFT using the driver information
center (DIC) or a scan tool.
2. Start and idle the engine.
3. Depress the brake pedal and move the shift lever
through each gear range.
3.1. Pause for at least 3 seconds in each range.
3.2. Move the shift lever back to PARK.
3.3. Ensure the engine RPM is low
(500–800 RPM).
4. Allow the engine to idle for a minimum time
of 1 minute.
Caution: THE ENGINE MUST BE RUNNING when the
trans oil level check plug is removed or excessive fluid
loss will occur, resulting in an under-filled condition. An
under-filled transmission will cause premature
component wear or damage.
5. Raise the vehicle on a hoist.
⇒ The vehicle must be level, with the engine
running and the shift lever in the PARK range.
Note: Continue to monitor the TFT. If the TFT is not
within the specified values, reinstall the trans oil level
check plug and repeat the previous steps.
6. Remove the transmission oil level check plug (1)
from the transmission fluid pan.
7. Allow any fluid to drain.
• If the fluid is flowing as a steady stream, wait
until the fluid begins to drip.
• If no fluid comes out, add fluid until fluid drips
out. Refer to Transmission Fluid Fill Procedure
in SI.
8. Reinstall the transmission oil level check plug.
Tighten
Torque the plug to 9Y(80 lb in).
9. Inspect for external leaks. Refer to Fluid Leak
Diagnosis in SI.
Page 8 June, 2019 Bulletin No.: 19-NA-121
Parts Information
Note: Only select the parts that coincide with the repair
performed.
Causal
Part
Description Part
Number
Qty
X Mobil 1 Synthetic
LV ATF HP
(Available only
through Local GM
Oil Distributors)
19417577
(US –
1 quart)
19418066
(Canada –
0.946L/1 qt)
20
N/A
Drum
55 gallon
19417904
(US)
1
N/A
RETAINER,
TRANS FLUID
CLR PIPE FTG
24205103 2
N/A SEAL, TRANS
FLUID CLR PIPE 23135703 1
Warranty Information
For vehicles repaired under the Powertrain coverage,
use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.
Labor
Operation
Description Labor Time
8480818* Diagnostic Testing and Fluid
Exchange
1.4 hrs
Add DT-45096 Prep (Not
required unless the fluid is
not Mobil 1 Synthetic LV
ATF HP)
0.1 hr
*This is a unique Labor Operation for Bulletin use only.
Version 1
Modified Released June 04, 2019

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