transmission GMC YUKON 2020 Service Manual

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 281
Vehicle Care
General Information
General Information . . . . . . . . . . 282
California Proposition65 Warning . . . . . . . . . . . . . . . . . 282
California Perchlorate Materials Requirements . . . . . 283
Accessories and Modifications . . . . . . . . . . . . . . . . 283
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 283
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 284
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 286
Engine Oil . . . . . . . . . . . . . . . . . . . . 289
Engine Oil Life System . . . . . . . 291
Automatic Transmission Fluid (6-Speed Transmission) . . . . . 292
Automatic Transmission Fluid (10-Speed Transmission) . . . 295
Engine Air Cleaner/Filter . . . . . . 296
Cooling System . . . . . . . . . . . . . . 297
Engine Overheating . . . . . . . . . . 300
Engine Fan . . . . . . . . . . . . . . . . . . . 302
Washer Fluid . . . . . . . . . . . . . . . . . 302
Brakes . . . . . . . . . . . . . . . . . . . . . . . 303 Brake Fluid . . . . . . . . . . . . . . . . . . . 304
Battery - North America . . . . . . 305
Four-Wheel Drive . . . . . . . . . . . . . 305
Front Axle . . . . . . . . . . . . . . . . . . . . 306
Rear Axle . . . . . . . . . . . . . . . . . . . . 306
Noise Control System . . . . . . . . 306
Starter Switch Check . . . . . . . . . 308
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 308
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 308
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 309
Wiper Blade Replacement . . . . 309
Glass Replacement . . . . . . . . . . 310
Windshield Replacement . . . . . 310
Gas Strut(s) . . . . . . . . . . . . . . . . . . 310
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 312
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 312
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . . . 312
LED Lighting . . . . . . . . . . . . . . . . . 312
Fog Lamps . . . . . . . . . . . . . . . . . . . 312
Back-Up Lamps . . . . . . . . . . . . . . 313
License Plate Lamp . . . . . . . . . . 314
Electrical System
Electrical System Overload . . . 314
Fuses and Circuit Breakers . . . 315
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 315
Instrument Panel Fuse Block
(Right) . . . . . . . . . . . . . . . . . . . . . . 320
Instrument Panel Fuse Block (Left) . . . . . . . . . . . . . . . . . 323
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 325
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 326
All-Season Tires . . . . . . . . . . . . . . 327
Winter Tires . . . . . . . . . . . . . . . . . . 328
Low-Profile Tires . . . . . . . . . . . . . 328
All-Terrain Tires . . . . . . . . . . . . . . . 328
Tire Sidewall Labeling . . . . . . . . 329
Tire Designations . . . . . . . . . . . . . 330
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . 331
Tire Pressure . . . . . . . . . . . . . . . . . 333
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . . . 334
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . . . . . . 335
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . 336
Tire Inspection . . . . . . . . . . . . . . . . 340

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 287
1. Positive (+) Terminal. SeeJump Starting - North America
0360.
2. Battery - North America 0305.
3. Coolant Surge Tank and Pressure Cap. See Cooling
System 0297.
4. Engine Air Cleaner/Filter 0296.
5. Automatic Transmission Dipstick. See “How to Check
Automatic Transmission Fluid”
under Automatic Transmission
Fluid (6-Speed Transmission)
0 292 or
Automatic Transmission Fluid
(10-Speed Transmission)
0 295.
6. Remote Negative (–) Location (Out of View). See Jump
Starting - North America 0360.
7. Engine Cooling Fans (Out of View). See Cooling System
0 297.
8. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil 0289. 9. Engine Oil Dipstick. See
“Checking Engine Oil” under
Engine Oil 0289.
10. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer Fluid
0 302.
11. Brake Fluid Reservoir. See Brake Fluid 0304.
12. Engine Compartment Fuse
Block 0315.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
292 Vehicle Care
best conditions, the oil life system
may indicate that an oil change is
not necessary for up to a year. The
engine oil and filter must be
changed at least once a year and,
at this time, the system must be
reset. Your dealer has trained
service people who will perform this
work and reset the system. It is also
important to check the oil regularly
over the course of an oil drain
interval and keep it at the proper
level.
If the system is ever reset
accidentally, the oil must be
changed at 5 000 km (3,000 mi)
since the last oil change.
Remember to reset the oil life
system whenever the oil is changed.
How to Reset the Engine Oil
Life System
Reset the system whenever the
engine oil is changed so that the
system can calculate the next
engine oil change. Always reset the
engine oil life to 100% after every oil
change. It will not reset itself. To
reset the engine oil life system:1. Display the REMAINING OIL
LIFE on the DIC. See Driver
Information Center (DIC) 0144.
2. Press and hold
V. The oil life
will change to 100%.
The oil life system can also be reset
as follows: 1. Display the REMAINING OIL LIFE on the DIC. See Driver
Information Center (DIC) 0144.
2. Fully press the accelerator pedal slowly three times within
five seconds.
3. Display the REMAINING OIL LIFE on the DIC. If the display
shows 100%, the system is
reset.
If the CHANGE ENGINE OIL SOON
message comes back on when the
vehicle is started and/or the
REMAINING OIL LIFE is near 0%,
the engine oil life system has not
been reset. Repeat the procedure.
Automatic Transmission
Fluid (6-Speed
Transmission)
When to Check and Change
Automatic Transmission Fluid
It is usually not necessary to check
the transmission fluid level. The only
reason for fluid loss is a
transmission leak or overheated
transmission. If a small leak is
suspected, then use the following
checking procedures to check the
fluid level. However, if there is a
large leak, then it may be necessary
to have the vehicle towed to a
dealer service department and have
it repaired before driving the vehicle
further.
Caution
Use of the incorrect automatic
transmission fluid may damage
the vehicle, and the damage may
not be covered by the vehicle
warranty. Always use the correct (Continued)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 293
Caution (Continued)
automatic transmission fluid. See
Recommended Fluids and
Lubricants0388.
Change the fluid and filter at the
scheduled maintenance intervals
listed in Maintenance Schedule
0 379. Be sure to use the
transmission fluid listed in
Recommended Fluids and
Lubricants 0388.
How to Check Automatic
Transmission Fluid
Caution
Too much or too little fluid can
damage the transmission. Too
much can mean that some of the
fluid could come out and fall on
hot engine parts or exhaust
system parts, starting a fire. Too
little fluid could cause the (Continued)
Caution (Continued)
transmission to overheat. Be sure
to get an accurate reading if
checking the transmission fluid.
Before checking the fluid level,
prepare the vehicle: 1. Start the engine and park the vehicle on a level surface.
Keep the engine running.
2. Apply the parking brake and place the shift lever in P (Park).
3. With your foot on the brake pedal, move the shift lever
through each gear range,
pausing for about
three seconds in each range.
Then, move the shift lever back
to P (Park).
4. Allow the engine to idle (500– 800 rpm) for at least
one minute. Slowly release the
brake pedal.
5. Keep the engine running and check the transmission fluid
temperature on the Driver Information Center (DIC). See
Driver Information Center (DIC)
0
144.
6. Using the transmission fluid temperature reading, determine
and perform the appropriate
check procedure. If the
transmission fluid temperature
reading is not within the
required temperature ranges,
allow the vehicle to cool,
or operate the vehicle until the
appropriate transmission fluid
temperature is reached.
Cold Check Procedure
Use this procedure only as a
reference to determine if the
transmission has enough fluid to be
operated safely until a hot check
procedure can be made. The hot
check procedure is the most
accurate method to check the fluid
level. Perform the hot check
procedure at the first opportunity.
Use this cold check procedure to
check fluid level when the
transmission temperature is
between 27 °C and 32 °C (80 °F and
90 °F).

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
294 Vehicle Care
1. Locate the transmissiondipstick at the rear of the
engine compartment, on the
passenger side of the vehicle.
See Engine Compartment
Overview 0286.
2. Flip the handle up, then pull out the dipstick and wipe it with a
clean rag or paper towel.
3. Install the dipstick by pushing it back in all the way; wait
three seconds, and then pull it
back out again.
4. Check both sides of the dipstick and read the lower
level. Repeat the check
procedure to verify the reading.5. If the fluid level is below theCOLD check band, add only
enough fluid as necessary to
bring the level into the COLD
band. It does not take much
fluid, generally less than 0.5 L
(1 pt). Do not overfill.
6. Perform a hot check at the first opportunity after the
transmission reaches a normal
operating temperature between
71 °C to 93 °C (160 °F to
200 °F).
7. If the fluid level is in the acceptable range, push the
dipstick back in all the way,
then flip the handle down to
lock the dipstick in place. Hot Check Procedure
Use this procedure to check the
transmission fluid level when the
transmission fluid temperature is
between 71 °C and 93 °C (160 °F
and 200 °F).
The hot check is the most accurate
method to check the fluid level. The
hot check should be performed at
the first opportunity in order to verify
the cold check. The fluid level rises
as fluid temperature increases, so it
is important to ensure the
transmission temperature is within
range.
1. Locate the transmission
dipstick at the rear of the
engine compartment, on the
passenger side of the vehicle.
See Engine Compartment
Overview 0286.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 295
2. Flip the handle up, then pull outthe dipstick and wipe it with a
clean rag or paper towel.
3. Install the dipstick by pushing it back in all the way; wait
three seconds, and then pull it
back out again.
4. Check both sides of the dipstick and read the lower
level. Repeat the check
procedure to verify the reading.
5. Safe operating level is within
the HOT cross hatch band on
the dipstick. If the fluid level is
not within the HOT band, and
the transmission temperature is
between 71 °C and 93 °C
(160 °F and 200 °F), add or
drain fluid as necessary to
bring the level into the HOT
band. If the fluid level is low, add only enough fluid to bring
the level into the HOT band.
It does not take much fluid,
generally less than 0.5 L (1 pt).
Do not overfill.
6. If the fluid level is in the acceptable range, push the
dipstick back in all the way,
then flip the handle down to
lock the dipstick in place.
Consistency of Readings
Always check the fluid level at least
twice using the procedure described
previously. Consistency (repeatable
readings) is important to maintaining
proper fluid level. If readings are still
inconsistent, contact the dealer.
Automatic Transmission
Fluid (10-Speed
Transmission)
When to Check and Change
Automatic Transmission Fluid
It is usually not necessary to check
the transmission fluid level. The only
reason for fluid loss is a transmission leak or overheated
transmission. This vehicle is not
equipped with a transmission fluid
level dipstick. There is a special
procedure for checking and
changing the transmission fluid in
these vehicles. Because this
procedure is difficult, this should be
done at the dealer. Contact the
dealer for additional information or
the procedure can be found in the
service manual. See
Publication
Ordering Information 0405.
Caution
Use of the incorrect automatic
transmission fluid may damage
the vehicle, and the damage may
not be covered by the vehicle
warranty. Always use the correct
automatic transmission fluid. See
Recommended Fluids and
Lubricants 0388.
Change the fluid and filter at the
scheduled maintenance intervals
listed in Maintenance Schedule
0 379. Be sure to use the

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
296 Vehicle Care
transmission fluid listed in
Recommended Fluids and
Lubricants0388.
Engine Air Cleaner/Filter
See Engine Compartment Overview
0 286 for the location of the engine
air cleaner/filter.
When to Inspect the Engine Air
Cleaner/Filter
For intervals on changing and
inspecting the engine air cleaner/
filter, see Maintenance Schedule
0 379.
How to Inspect the Engine Air
Cleaner/Filter
Do not start the engine or have the
engine running with the engine air
cleaner/filter housing open. Before
removing the engine air cleaner/
filter, make sure that the engine air
cleaner/filter housing and nearby
components are free of dirt and
debris. Remove the engine air
cleaner/filter. Lightly tap and shake
the engine air cleaner/filter (away
from the vehicle), to release loose dust and dirt. Inspect the engine air
cleaner/filter for damage, and
replace if damaged. Do not clean
the engine air cleaner/filter or
components with water or
compressed air.
To inspect or replace the engine air
cleaner/filter:
1. Screws (4)
2. Electrical Connector
3. Air Duct Clamp
1. Locate the air cleaner/filter
assembly. See Engine
Compartment Overview 0286. 2. Disconnect the outlet duct by
loosening the air duct
clamp (3).
3. Disconnect the electrical connector (2) and the
connector harness from the
cover.
4. Remove the four screws (1) on top of the cover of the housing
and lift up the cover.
5. Remove the engine air cleaner/ filter from the housing. Take
care to dislodge as little dirt as
possible.
6. Clean the engine air cleaner/ filter sealing surfaces and the
housing.
7. Inspect or replace the engine air cleaner/filter.
8. Reverse Steps 2-4 to reinstall the filter cover housing.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
308 Vehicle Care
Starter Switch Check
{Warning
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle.
2. Apply both the parking brake and the regular brake.
Do not use the accelerator
pedal, and be ready to turn off
the engine immediately if it
starts.
3. Try to start the engine in each gear. The vehicle should start
only in P (Park) or N (Neutral).
If the vehicle starts in any other
position, contact your dealer for
service.
Automatic Transmission
Shift Lock Control
Function Check
{Warning
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Apply the parking brake. Be ready to apply the regular
brake immediately if the vehicle
begins to move.
3. With the engine off, turn the ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with normal effort. If the shift lever
moves out of P (Park), contact
your dealer for service.
Ignition Transmission
Lock Check
If equipped with a Key Access
ignition, while parked and with the
parking brake set, try to turn the
ignition off in each shift lever
position.
.
The ignition should turn off only
when the shift lever is in
P (Park).
. The key should come out only
when the ignition is off.
Contact your dealer if service is
required.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 309
Park Brake and P (Park)
Mechanism Check
{Warning
When you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move.
Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake.
. To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot
pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only. .
To check the P (Park)
mechanism's holding ability:
With the engine running, shift to
P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement
Windshield wiper blades should be
inspected for wear or cracking.
For the proper type and size, see
Maintenance Replacement Parts
0 390.
Caution
Allowing the wiper arm to touch
the windshield when no wiper
blade is installed could damage
the windshield. Any damage that
occurs would not be covered by
the vehicle warranty. Do not allow
the wiper arm to touch the
windshield.
Front Wiper Blade
Replacement
To replace the wiper blade
assembly:
1. Pull the windshield wiper assembly away from the
windshield.
2. Lift up on the latch in the
middle of the wiper blade
where the wiper arm attaches.
3. With the latch open, pull the wiper blade down toward the
windshield far enough to
release it from the J-hooked
end of the wiper arm.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Vehicle Care 319
FusesUsage
45 Automatic level control/Run/Crank
46 –
47 Upfitter 4
49 Reverse lamps
50 –
52 –
53 –
54 –
55 –
56 –
57 –
58 –
59 Euro trailer
60 Air conditioning control
61 –
62 –
63 Upfitter 1
64 – Fuses
Usage
65 –
66 –
67 Trailer battery
68 Secondary fuel pump
69 RC upfitter 3 and 4
70 VBAT upfitter 3 and 4
71 –
73 –
74 Engine control module/Ignition
75 Miscellaneous/ Ignition/–
76 Transmission/ Ignition
77 RC upfitter 1 and 2
78 VBAT upfitter 1 and 2
79 –
80 –
81 – Fuses
Usage
82 –
83 Euro trailer/RC
85 –
86 –
87 MAF/IAT/Humidity/ TIAP sensor
88 Injector A –odd
89 Injector B –even
90 O2 sensor B
91 Throttle control
93 Horn
94 Fog lamps
95 High-beam headlamps
96 –
97 –
98 –
99 –
100 O2 sensor A
101 Engine control module