Bulletin No.:

Service Bulletin

Date:

20-NA-136
August, 2023

INFORMATION
Subject:

Diagnostic Tips for DTCs Set at a Low Mileage for 9T65 Transmissions

Attention: The 9T65 Transmission Replacement Pilot Has Ended.

This bulletin only applies to vehicles with less than 19,000 km (12,000 miles) on the
odometer. Vehicles over the mileage refer to SI diagnostics.

Brand:

Model:

Buick

Enclave

Cadillac
Chevrolet
GMC

Model Year:
from

to

VIN:
from

to

Engine:

XT5
XT6
Blazer

M3W
2021

2024

—

Acadia

—

M3W

United States, Canada, Middle East

Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict between
the procedures set forth in this bulletin and the
laws that apply to your dealership, you must follow
those applicable laws.

Overview
The 9T65 transmission replacement pilot program has
ended as of September 30, 2021 with the end of the
pilot program mandatory transmission assembly
replacement is no longer authorized per this bulletin.
Instead refer to bulletin 20-NA-138 for current
guidelines for replacement of transmission assemblies.
This bulletin is being revised to convey this change and
to provide an enhanced diagnostic and repair strategy
developed through the pilot program teardown and
inspection learnings from returned transmissions.
These strategy changes will keep with the intent of the
Copyright 2023 General Motors LLC. All Rights Reserved.

—

M3V

Traverse

Involved Region or Country

Transmission:

replacement pilot program to reduce the number of
days to complete the vehicle repair and reduce the
number of repeat repair visits.
Unlike the replacement pilot program which was only
for the US dealers this diagnostic and repair strategy
can be used by all dealerships servicing vehicles with
9T65 transmissions.
If a customer is commenting on transmission operation
concerns on a 9T65 transmission (RPO M3W and
M3V), follow the steps below to determine repair
strategy.
Please refer to these service publications for
resolutions to customer comments prior to proceeding
with this bulletin.
1. 18-NA-359 – Information on Flashing D in PRNDL
and/or Transmission Slip/Flare on 1-2 Upshift with
Zero to Very Light Throttle Input
2. 20-NA-060 – High Pitch Noise Heard When
Vehicle is Decelerating

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August, 2023

3. 21-NA-201 – Information on DTC P0747 Setting at
Engine Shut Down When Transmission is in Park/
Neutral with No Hydraulic/Mechanical
Transmission Concern
4. 21-NA-038 – Humming Noise Heard Coming From
Front End of Vehicle When Driving at Highway
Speeds
5. 21-NA-118 - Vibration Type Noise Heard at
Highway Speeds or with Engine Speed at
1,300-1,500 RPM
6. Torque converter shudder.
• Refer to PIP5608H – TCC Shudder Surge Fish
bite Chuggle
• Refer to latest version of 08-07-30-035 –
Information on Water or Ethylene Glycol in
Transmission Fluid
• Refer to Torque Converter Diagnosis in SI.
• If not resolved, contact Technical Assistance
(TAC). Refer to PIP5621B: GM TAC Support On
Vehicle Automatic Transmission Concerns That
Can Be Duplicated
7. In addition to the complaint, cause, and correction
notes on the repair order, this other information is
required to be noted:
• DTCs found during vehicle diagnosis – include
the DTC, what module it was in and if it was
history or current. Search all modules including
TCM, ECM, BCM, EBCM, IPC, and TRCM.
• Oil level test findings – overfill, under-fill, and
correct level. If over or under, estimate of how
much fluid.
• Oil pressure test results. Record actual
pressure reading taken.

Step One — DTCs
1. Check all Modules for DTCs. Records of all DTCs,
Current or History, and Module Located In/On
Repair Order.

Step Two — Fluid Level and Condition Check
Note: Ensure the transmission has enough fluid in it to
safely start the vehicle without damaging the
transmission. With the vehicle off and the transmission
fluid temperature at approximately 20–25°C (68–77°F),
there must be at least enough fluid to drain out of the
fluid level hole. This will ensure that there is enough
fluid in the sump to fill the components once the vehicle
is started.
1. Start the engine.
2. Depress the brake pedal and move the shift lever
through each gear range, pausing for about 3
seconds in each range. Then move the shift lever
back to PARK (P).
3. Allow the engine to idle 500–800 rpm for at least 3
minutes to allow any fluid foaming to dissipate and
the fluid level to stabilize. Release the brake pedal.
4. Keep the engine running and observe the
transmission fluid temperature (TFT) using the
Driver Information Center (DIC) or a scan tool.

Bulletin No.: 20-NA-136

Caution: The transmission fluid level must be checked
when the transmission fluid temperature (TFT) is at 85–
95°C (185–203°F). If the TFT is not at this temperature,
operate the vehicle or allow the fluid to cool as
required. Setting the fluid level with a TFT outside this
temperature will result in either an under or over-filled
transmission. TFT 95°C under-filled, TFT 85°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, fluid foaming, or pump cavitation.
5. Raise the vehicle on a hoist. The vehicle must be
level, with the engine running and the shift lever in
the PARK range.

5619626

6. While the vehicle is idling, remove the oil level set
plug (1). 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.
7. Record fluid level; overfilled, under-filled, correct
on repair order and how much was needed to fill or
came out:
• If fluid is overfilled, set correct level and retest.
• If fluid is under-filled, inspect for external leaks.
Refer to Fluid Leak Diagnosis.
8. If fluid level is correct, then check condition of the
fluid.

Bulletin No.: 20-NA-136

August, 2023

Page 3

water and repair then follow SI document
for “Engine Coolant/Water in Transmission”
for proper transmission repair.
8.3. Inspect for external leaks. Refer to Fluid Leak
Diagnosis.
– If fluid level and condition are ok, proceed to
next step.

Step Three — Line Pressure Check
Warning: Keep the brakes applied at all times in
order to prevent unexpected vehicle motion.
Personal injury may result if the vehicle moves
unexpectedly.
Note: You may need to remove or disconnect
components in order to gain access to the transmission
line pressure test hole plug.

5840393

8.1. Inspect the fluid color.
– The fluid should be red or dark brown.
– It should be transparent so that objects or
writing can be seen through it. Sample #1 is
an example of acceptable fluid. Sample #2
is an example of very dark fluid. Sample #3
is an example of black fluid.
– In addition to checking the fluid color and
transparency, the fluid should be checked
for an odor of burnt fluid. If the fluid is very
dark, black, or has a burnt odor it would
indicate clutch damage has occurred
internally in the transmission and it would
need to be removed from the vehicle and
investigated.
8.2. Inspect the fluid for excessive metal particles
or other debris.
– A small amount of “friction” material is a
“normal” condition.
– A small amount of “metal” from the
manufacturing process is a “normal”
condition. This is observed as fine silver
streaks floating in the fluid.
– If large pieces and/or metal pieces are
noted in the fluid, record on the repair order
and it would indicate damage has occurred
internally in the transmission and it would
need to be removed from the vehicle and
investigated.
– Fluid that is cloudy or milky or appears to be
contaminated with water indicates engine
coolant or water contamination. Refer to the
latest version of Corporate Service Bulletin
Number 08-07-30-035 for testing and, if
confirmed, find the source of the coolant/

1. Remove the line pressure test hole plug. Refer to
Automatic Transmission Fluid Pressure Test Hole
Plug Replacement in SI.
2. Install the GE-21867 Pressure Gauge (1).
3. Start the engine.
4. Verify the Transmission Fluid Pressure = Greater
than 345 kPa (50 psi).
• If pressure is below 50 psi, record on the repair
order and follow SI document for “Fluid
Pressure High of Low”.
• If above 50 psi, proceed to next step.
5. Turn the engine OFF.
6. Remove the GE-21867 Pressure Gauge.
7. Install and tighten line pressure test hole plug.
Refer to Automatic Transmission Fluid Pressure
Test Hole Plug Replacement in SI.

Step Four — Perform Road Test
Perform step 1-4 first in order to ensure the electronic
transmission components are functioning properly. If
these components are not checked, a simple electrical
condition could be misdiagnosed.
1. Connect the scan tool.
2. Ensure the gear selector is in PARK and set the
parking brake.
3. Start the engine.
4. Verify that the following scan tool data can be
obtained and is functioning properly.
– Refer to Control Module References for typical
data values. Data that is questionable may
indicate a concern.
5. Check the garage shifts.
5.1. Apply the brake pedal and ensure the parking
brake is set.
5.2. Move the gear selector through the following
ranges:
⇒ PARK to REVERSE
⇒ REVERSE to NEUTRAL
⇒ NEUTRAL to DRIVE
⇒ DRIVE to REVERSE
⇒ REVERSE to DRIVE

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August, 2023

5.3. Pause 2 to 3 seconds in each gear position.
5.4. Verify the gear engagements are immediate
(less than 2 seconds to complete if
transmission fluid temperature is above 20°
C (68°F) and not harsh. Note that these shifts
may be almost imperceptible in some
applications. Using the scan tool to monitor
Transmission ISS, achieving 0 rpm can be
used to check delay in these cases.
Note: Harsh engagement may be caused by any of the
following conditions:
– High engine idle speed – Compare engine
idle speed to desired idle speed.
– A default condition caused by certain DTCs
that result in maximum line pressure to
prevent clutch slippage.
– Incomplete adapting or incorrect adapting –
Repeat maneuver multiple times to see if
shift quality improves. If it does not and no
DTCs were set, refer to SI document
“Harsh Garage Shift”.
Note: Delayed engagement may be caused by any of
the following conditions:

6.

⇒
⇒
⇒
⇒
⇒
⇒
⇒
⇒
⇒
⇒
⇒
⇒
⇒
⇒

– Low idle speed – Compare engine idle
speed to desired idle speed.
– Low fluid level.
– Cold transmission fluid temperature (TFT)
– Use the scan tool to determine TFT.
– Selector linkage – Inspect and adjust as
necessary.
– Incomplete adapting or incorrect adapting –
Repeat maneuver multiple times to see if
the delay improves. If it does not and no
DTCs were set, refer to SI document