not allow Autostop to occur.
Autostop Disable Switch
The disable switch is an input to the BCM and allows
the customer to disable or re-enable the autostop
system. After the vehicle is turned off, the autostop
system turns back on the next time the vehicle is
started.

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The non-latching disable switch is located to the left of
the steering column and above the headlamp switch.
Power Supply Transformer
The DC to DC converter monitors battery voltage and
will maintain operating voltage to the radio, instrument
cluster, and instrument panel displays. The DC to DC
converter will provide a boosted voltage to sensitive
loads during autostart to ensure proper operation of the
driver informational displays.
Instrument Cluster
In order to differentiate between a normal engine
shutdown (engine speed 0 RPM) and when the engine
has been shut down by the stop/start system, the
tachometer needle will rest at the Autostop indicator
icon (500 RPM point) indicating the engine has been

Bulletin No.: 20-NA-211

October, 2020

shut down by the Stop/Start System. Once the engine
is restarted, or the ECO button has disengaged
autostop, the tachometer will function normally.

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2-Speed Automatic Transfer Case

Dual Exhaust System

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For better engine breathing, a dual exhaust system is
standard with the 6.2L (L87) V8 engine. The dual
exhaust system is not available with the 3.0L (LM2) I6
engine.

Driveline/Axle
Overview
The 2021 Cadillac Escalade driveline uses a
Rear-Wheel Drive (RWD) configuration with a
longitudinally mounted engine and transmission. In
Four-Wheel Drive (4WD) vehicles, a transfer case
directs power to the front and rear axles, or the rear
axle only, depending on driver selection. Two-Wheel
Drive (2WD) vehicles do not use a transfer case. In
2WD vehicles, power transfers directly from the
transmission to the rear axle to propel the vehicle.

Transfer Cases
Transfer cases are found on 4WD vehicles and are
responsible for dividing the power to all four wheels.

The 3025 (NQH) transfer case is a 2-speed, automatic,
active transfer case. A 5-mode shift control switch
(shown circled above) is located on the instrument
panel. When the ignition key is in the RUN position, the
transfer case shift control module monitors the transfer
case shift control switch to determine if the driver
desires a new mode/range position. The transfer case
is electronically controlled for a seamless select though
all modes. The driver can select AUTO 4WD position
and four manual mode/range positions.
• AUTO range
• 4HI – 4-wheel drive high range
• 2HI – 2-wheel drive high range
• 4LO – 4-wheel drive low range, 2.72:1 gear ratio
reduction
• NEUTRAL
4LO
The driver may choose to select any of these mode/
range positions while driving the vehicle. However, the
transfer case will not allow a shift into or out of 4LO
unless the following criteria have been met:
• The ignition switch is in RUN
• The automatic transmission is in NEUTRAL
• The vehicle speed is below 5 km/h (3 mph).
NEUTRAL
1. Start the vehicle or turn the ignition to RUN
2. Shift the transmission to N (NEUTRAL).
3. Shift the transfer case to 2HI (shifts to transfer
case NEUTRAL are only allowed when transfer
case initial state is 2HI).
4. Apply the parking brake and/or service brake (if the
parking brake and/or service brake is not applied
within 20 seconds, the transfer case will remain in
its original state).
5. Press 2HI five times in 10 seconds until the transfer
case N indicator starts blinking in the cluster. When
the shift to N is complete, the indicator in the
cluster illuminates steady.

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October, 2020

AUTO 4WD
AUTO 4WD is a full-time system that lets the vehicle
operate in 2WD (either front or rear) until the system
judges that 4WD is needed. AUTO 4WD provides the
benefits of an on-demand torque biasing wet clutch and
easy vehicle tuning through software calibrations.
In AUTO 4WD mode, the transfer case shift control
module monitors rear wheel slip speed based on the
inputs from the wheel speed sensors and/or the vehicle
speed sensor. When the vehicle experiences a rear
wheel slip condition, the transfer case shift control
module sends a Pulse Width Modulated (PWM) signal
to the transfer case two/four-wheel drive actuator. The
two/four-wheel drive actuator rotates the transfer case
control actuator shaft, applying a clutch. The clutch is
designed to deliver a variable amount of torque. The
clutch normally delivers torque to the rear wheels and
transfers it to the front wheels. Torque is ramped up to
the front wheels until the front wheel speed sensors
match that of the rear wheel speed sensors and/or the
vehicle speed sensor. Torque is then ramped down to
the front wheels. The process repeats if rear wheel slip
is detected again.
1-Speed Automatic Transfer Case
The 3015 (NPO) transfer case is a 1-speed automatic,
active transfer case that provides three modes: Auto
4WD, 4HI, and 2HI.

Bulletin No.: 20-NA-211

Front Axle Description and Operation
The front axle on selectable 4WD vehicles uses a
central disconnect feature in order to engage and
disengage the front axle. When the driver engages the
4WD system, the transfer case control module sends a
signal to the electric motor actuator to energize and
extend the plunger inside. The extended plunger
moves the clutch fork and clutch fork sleeve across the
inner axle shaft and the clutch fork shaft, and it locks
the two shafts together. The locking of the two shafts
allows the axle to operate in the same manner as a
semi-floating rear axle. A propeller shaft connects the
transfer case to the front axle.
The differential carrier assembly uses a conventional
ring and pinion gear set to transmit the driving force of
the engine to the wheels. The open differential allows
the wheels to turn at different rates of speed while the
axle continues to transmit the driving force. This
prevents tire scuffing when going around corners and
premature wear on internal axle parts. The ring and
pinion set and the differential are contained within the
carrier.
The axle identification number is located on top of the
differential housing assembly or on a label on the
bottom of the right half of differential carrier assembly.
The wheel drive shafts are flexible assemblies. Inner
and outer constant velocity joints are protected by
thermoplastic boots and connected by a front wheel
driveshaft.

Limited Slip Rear Differentials

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Shifts between any driving mode may be made at
normal driving speed.

Front Drive and Rear Drive Axles
The 2021 Cadillac Escalade has two new rear axles.
The solid rear axle has been replaced with a rear drive
module to allow for the G86 limited slip rear axle and
the electronic G96 positraction limited slip axle. This
supports the independent rear suspension. The front
axle remains unchanged.

Standard G86 Limited Slip Rear Differential
The limited rear differential is a mechanical standard
differential that provides excellent traction with
seamless engagement and disengagement locking.
The G86 limited slip rear differential consists of the
following components:
• differential case
• pinion gear shaft
• differential pinion gear shaft lock bolt
• two clutch discs sets
• locking differential side gears
• thrust block
• locking differential clutch disc guides
• differential side gear shim
• locking differential clutch disc thrust washer
• locking differential governor
• latching bracket
• cam plate assembly
• differential pinion gears
• differential pinion gear thrust washers

Bulletin No.: 20-NA-211

October, 2020

Operation
The base G86 mechanical limited slip rear differential
enhances the traction capability of the rear axle by
combining the characteristics of a limited-slip
differential and the ability of the axle shafts to lock
together as required. The G86 provides traction without
abrupt engagement/disengagement locking thump. The
differential accomplishes this in two ways. First, a
series of clutch plates at each side of the differential
case limits the amount of slippage between each
wheel. Second, a mechanical locking mechanism stops
the rotation of the right differential side gear, in order to
transfer the rotating torque of the wheel without traction
to the wheel with traction. When the axle locks it drives
both wheels. Each function occurs under different
conditions.
Limited Slip Function
Under normal conditions, when the differential is not
locked, a small amount of limited slip action occurs.
The gear separating force developed in the right-hand
clutch pack is primarily responsible for this.
The operation of the limited slip function of the unit can
be explained when the vehicle makes a right-hand turn.
Since the left wheel travels farther than the right wheel,
it must rotate faster than the ring gear and differential
case assembly. This results in the left axle and left-side
gear rotating faster than the differential case. The faster
rotation of the left-side gear causes the pinion gears to
rotate on the pinion shaft. This causes the right-side
gear to rotate slower than the differential case.
The side gear spreading force produced by the pinion
gears compresses the clutch packs, primarily the right
side. However, the friction between the tires and the
road surface is sufficient to overcome the friction of the
clutch packs. This prevents the side gears from being
held to the differential case.
Locking Function
The locking action occurs through the use of the
following component parts:
• a governor mechanism with two flyweights
• a latching bracket
• the left-side cam plate and cam side gear
When the wheel-to-wheel speed difference is 100 RPM
or under 32 km/h (20 MPH), the flyweights of the
governor will fling out and one of them will contact an
edge of the latching bracket. This happens because the
left cam side gear and cam plate are rotating at a speed
different, either slower or faster, than that of the ring
gear and differential case assembly. The cam plate has
teeth on its outer diameter surface in mesh with teeth
on the shaft of the governor.
As the side gear rotates at a speed different than that of
the differential case, the shaft of the governor rotates
with enough speed to force the flyweights outward
against spring tension. One of the flyweights catches its
edge on the closest edge of the latching bracket, which
is stationary in the differential case.

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The latching process triggers a chain of events:
1. When the governor latches, it stops rotating. A
small friction clutch inside the governor allows
rotation, with resistance, of the governor shaft
while one flyweight is held to the differential case
through the latching bracket. The purpose of the
governor's latching action is to slow the rotation of
the cam plate as compared to the cam side gear.
This will cause the cam plate to move out of its
detent position.
2. The cam plate normally is held in its detent position
by a small wave spring and detent humps resting in
matching notches of the cam side gear. At this
point, the ramps of the cam plate ride up on the
ramps of the cam side gear, and the cam plate
compresses the left clutch pack with a
self-energizing action.
3. As the left clutch pack is compressed, it pushes the
cam plate and cam side gear slightly toward the
right side of the differential case. This movement of
the cam side gear pushes the thrust block, which
compresses the right-hand side gear clutch pack.
4. At this point, the force of the self-energizing
clutches and the side gear separating force
combine to hold the side gears to the differential
case in the locking stage.
Available G96 Electronic Limited Slip Rear
Differential
An available G96 electronic locking rear differential
enhances the traction capability of the rear axle by
reacting instantaneously to a loss of traction.
The K164 differential control module’s function is to
control the electronic limited slip differential. The
module receives a torque request through the CAN bus
and applies torque to the rear differential. The K164
control module is located in the trunk compartment.
The differential system contains the following main
components:
• M135 differential lock motor
• position sensor (internal to motor)
• temperature sensor (internal to motor)
The locking torque causes a multiplication of wheel
torque, which can be used to improve traction and/or
vehicle dynamics. The M135 differential lock motor
actuates a multidisc friction clutch via a reduction gear
set. The M135 differential lock motor is used to close
and open the clutch. The module controls the
differential lock motor and monitors the differential
sensors via the high speed CAN bus.

Transmission
Overview
The 2021 Cadillac Escalade is equipped with the
Hydra-Matic 10L80 (MQC) 10-speed automatic
transmission.
Transmission Identification Information
Identification information for the 10-speed 10L80
(MQC) transmission is located at the rear of the
transmission. The transmission identification code
contains the information shown in the graphic below.

Page 22

October, 2020

Bulletin No.: 20-NA-211

10L80 (MQC) Automatic Transmission
Components
The 10L80 (MQC) automatic transmission includes the
following key components:
Transmission Control Module
The TCM is externally mounted at the left front of the
vehicle to the rear of the under hood fuse box. The
controller makes use of four speed sensors. The TCM
is part of a network of other control modules on the
vehicle. The control modules share information with
each other over a common serial data communications
line. Based upon the TCM software/calibrations and
input information, the TCM has final authority of when
to allow an upshift or downshift whether in manual
mode operation or in a drive position for automatic
shifting.

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1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.

Broadcast Code
Source DUNS Number
Transmission Unique Number
2D Machine Readable Matrix
VPPS Code
Part Sequence Number
Site ID
Broadcast Code
Julian Date
Year of Build
Shift ID
Line Plant ID
GM Part Number

10L80 (MQC) Automatic Transmission
The Hydra-Matic 10L80 (MQC) transmission is a heavy
duty, fully automatic, 10-speed, electronically controlled
transmission. This transmission features a push button
Electronic Transmission Range Selector (ETRS)
located on the instrument panel, as well as stop/start
technology.
The transmission architecture features a case with
integral bell housing for enhanced powertrain stiffness.
A unique off-axis pump drive design allows for very low
mounting in the transmission.
10L80 (MQC) Automatic Transmission Approximate
Fluid Capacities:
• Pan Removal and Filter Replacement –
Approximate Capacity: 7.7 liters (8.1 quarts)
• Overhaul – Approximate Capacity
(Transmission Volume Only): 10.95 liters (11.57
quarts)
• Complete Transmission System – Approximate
Capacity (Including Cooler Volume): 11.44 liters
(12.08 quarts)

Transmission Fluid Pump
The transmission fluid pump is a variable vane type,
which is an off-axis gear-driven pump next to the valve
body assembly. The pump maintains the hydraulic fluid
pressures needed to apply the clutch pistons that apply
or release the friction components
Torque Converter
The torque converter acts as a fluid coupling to
smoothly transmit power from the engine to the
transmission. It also hydraulically provides additional
torque multiplication when required. The pressure
plate, when applied, provides a mechanical direct drive
coupling of the engine to the transmission.
The torque converter and electronically controlled
capacity clutch reduce the possibility of noise, vibration,
or chuggle caused by Torque Converter Clutch (TCC)
apply. In a torque converter with an electronically
controlled capacity clutch, the pressure plate does not
always fully lock to the torque converter cover. Instead,
the pressure plate maintains a small amount of
slippage. In Rear-Wheel Drive (RWD) 10-speed
transmissions, this slippage can range from 0–50 RPM.
Full lockup (0 RPM slip) is still available on some
applications. The TCC may apply in 1st through 10th
gear. The specific TCC apply points and the amount of
clutch slippage are determined by a number of
operating conditions, including throttle position, vehicle
speed, and gear, as well as specific vehicle
applications. Transmission fluid temperature also
affects TCC apply points.
Friction Components
The friction components within the 10L80 (MQC)
automatic transmission are the clutch assemblies.
Switches and Speed Sensors
The 10L80 MCQ transmission has the following
switches and speed sensors:
• automatic transmission fluid temperature sensor
• automatic transmission input speed sensor
• automatic transmission intermediate speed
sensor 1

Bulletin No.: 20-NA-211
•
•

October, 2020

automatic transmission intermediate speed
sensor 2
automatic transmission output speed sensor 1

Planetary Gear Sets
The four planetary gear sets provide ten forward gear
ratios and REVERSE. Changing gear ratios is fully
automatic and is accomplished through the TCM. The
TCM receives and monitors various electronic sensor
inputs and uses this information to shift the
transmission using output controls.
Valve Body Assembly
The valve body controls the flow of the hydraulic
system. The 10-speed transmission could contain a
maximum of nine individual solenoids — RPO
dependent — installed in various bore locations on the
lower control valve body assembly. Eight of the nine
solenoid valves are used to control pressure regulation
and direction of transmission fluid. The one ON/OFF
solenoid valve is only used to direct transmission fluid.
The control solenoid valve body contains eight
transmission pressure control solenoids and one
direction control solenoid.

Electronic Transmission Range Selector

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The ETRS system replaces the conventional gearshift
on the 2021 Cadillac Escalade. The ETRS system is a
shift-by-wire system. There is no physical link between
the selector controls and the transmission. Electronic
shifting and eliminating the shift cable helps eliminate
noise and vibration from entering the vehicle. The push
and pull buttons are backlit, rubber-coated, and located
on the instrument panel.
The A97 Transmission Range Selector Controls in the
ETRS system has no mechanical linkage to the
transmission. Instead, the A97 Transmission Range
Selector Controls will provide electrical signals based
on customer input to the Engine Control Module, where
the customer shift request will be determined.

Page 23

The A97 Transmission Range Selector Controls
Assembly includes:
• PARK Button — The PARK button has two internal
contacts and a single push button. Its normally
open switch is closed when the button is pressed.
Actuation is one push.
• REVERSE Button — The REVERSE button has
three internal contacts and a single pull button. Its
normally open switch is closed when the button is
pressed. Actuation is one pull.
• NEUTRAL Button — The NEUTRAL button has
three internal contacts and a single push button.
Its normally open switch is closed when the button
is pressed. Actuation is one push
• DRIVE Button — The DRIVE button has three
internal contacts and a single pull button. Its
normally open switch is closed when the button is
pressed. Actuation is one pull.
• MANUAL/LOW Button — The MANUAL/LOW
button has one internal contact and a single push
button. Normally open switch that is closed when
the button is pressed. Actuation is one push.
The vehicle is equipped with the following Electronic
Transmission Range Selector Components:
• A97 Transmission Range Selector Controls
• K20 Engine Control Module
• K71 Transmission Control Module
ETRS uses the A97 Transmission Range Selector
Controls to select each gear range. When the driver
selects a specific range, the A97 Transmission Range
Selector Controls provide an electrical signal (based on
the driver’s selection) to the K20 Engine Control
Module. The K20 Engine Control Module sends a serial
data signal to the K71 Transmission Control Module to
shift the transmission into the selected range.
Latent Fault Mode
When the ETRS system detects a fault, the driver
information center displays the message SERVICE
TRANSMISSION NOW, UNABLE TO SHIFT SOON
accompanied by a 10-second chime. The system
forces the driver to acknowledge the message in order
to show other data on the driver information center. The
frequency of the message and chime increases until 50
trips have occurred with the fault present. At that point,
an UNABLE TO SHIFT message will display and the
transmission will not be allowed to shift out of PARK.
When the SERVICE SHIFTER SEE OWNER’S
MANUAL message is shown on the driver information
center, the shift lever requires service. If the vehicle is
automatically shifting into P (PARK), check to see if the
PARK button is stuck by running through the shifter
electrical diagnostics. To operate the vehicle, hold the
shift lever in the desired gear, R (REVERSE) or D
(DRIVE), until the vehicle speed exceeds 15 km/h
(10 MPH), and then release the shift lever.
Critical Fault Mode
When the ETRS system detects a fault and cannot
determine either the requested or the actual gear
position, the vehicle remains in the current commanded
gear position until the vehicle speed is below 9 km/h
(6 MPH). In order to lower vehicle speed, the Electronic

Page 24

October, 2020

Brake Control Module (EBCM) sends a command to
engage braking. When the vehicle speed falls below 8
km/h (5 MPH), the vehicle engages the electronic
parking brake and backup parking lock (also known as
Default to Park). The electronic parking brake will not
disengage until the issue is corrected and all related
Diagnostic Trouble Codes (DTCs) are cleared.
Neutral Service Mode
The neutral service mode allows the vehicle to remain
in NEUTRAL for use in automatic car washes where
the driver exits the vehicle. This mode is used when
bringing the vehicle into the service bay area.
Manual Park Release
This vehicle is NOT equipped with a manual park
release.

Service Considerations
Solenoid Characterization Reprogramming
Transmission control solenoid valves are pressure
regulating valves. Each solenoid valve is tested after
assembly to determine the output fluid pressure at
certain electrical current values, applied to the coil
windings. This information is referred to as solenoid
current/pressure data points. The solenoid valves are
tested two ways, with an increasing and decreasing
electrical current applied to the coil windings. The
resulting current versus pressure data points are saved
and assigned a file number. The file number is marked
on the solenoid valve housing end. The performance
data file is stored on the TIS2Web site. This data file is
programmed and stored in the vehicle’s TCM.