2021 GMC SIERRA automatic transmission

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
392 Vehicle Care
Caution (Continued)
to start the vehicle by pushing or pulling
it will not work, and it could damage the
vehicle.
1. Good Battery Positive Terminal
2. Good Battery Negative Terminal
3. Discharged Battery Remote NegativeTerminal
4. Discharged Battery Remote Positive Terminal
The jump start positive post (1) and negative
post (2) are on the battery of the vehicle
providing the jump start. The jump start positive post (4) and the
negative grounding point (3) for the
discharged battery are on the passenger side
of the vehicle.
The positive jump start connection for the
discharged battery is under a cover. Slide
the cover to expose the terminal.
1. Check the other vehicle. It must have a 12-volt battery with a negative ground
system.
Caution
If the other vehicle does not have a
12-volt system with a negative ground,
both vehicles can be damaged. Only use
a vehicle that has a 12-volt system with a
negative ground for jump starting.
2. If you have a vehicle with a diesel engine with two batteries, you should
know before you begin that, especially in
cold weather, you may not be able to
get enough power from a single battery
in another vehicle to start your diesel
engine. If your vehicle has more than
one battery, using the battery that is
closer to the starter will reduce electrical resistance. This is located on the
passenger side, in the rear of the engine
compartment.
3. Get the vehicles close enough so the jumper cables can reach, but be sure the
vehicles are not touching each other.
If they are, it could cause an unwanted
ground connection. You would not be
able to start your vehicle, and the bad
grounding could damage the electrical
systems.
To avoid the possibility of the vehicles
rolling, set the parking brake firmly on
both vehicles involved in the jump start
procedure. Put the automatic
transmission in P (Park) before setting
the parking brake. If you have a
four-wheel-drive vehicle, be sure the
transfer case is in a drive gear, not in
N (Neutral).
Caution
If any accessories are left on or plugged
in during the jump starting procedure,
they could be damaged. The repairs
would not be covered by the vehicle
warranty. Whenever possible, turn off or
unplug all accessories on either vehicle
when jump starting.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Service and Maintenance 411
missing boots, loose or missing boot
clamps, center bearing excessive
looseness, missing or loose fasteners.
.Check restraint system components. See
Safety System Check060.
.Visually inspect fuel system for damage
or leaks.
.Visually inspect exhaust system and
nearby heat shields for loose or damaged
parts.
.Lubricate body components. See Exterior
Care 0398.
.Check starter switch. See Starter Switch
Check 0347.
.Check automatic transmission shift lock
control function. See Automatic
Transmission Shift Lock Control Function
Check 0347.
.Check ignition transmission lock. See
Ignition Transmission Lock Check 0347.
.Check parking brake and automatic
transmission park mechanism. See Park
Brake and P (Park) Mechanism Check
0 347.
.Check accelerator pedal for damage, high
effort, or binding. Replace if needed.
.Visually inspect gas strut for signs of
wear, cracks, or other damage. Check the
hold open ability of the strut. If the hold
open is low, service the gas strut. See Gas
Strut(s) 0349.
.Inspect sunroof track and seal,
if equipped. See Sunroof043.
.Verify spare tire key lock operation and
lubricate as needed. See Tire Changing
0 381.
.Visually inspect the spare tire to ensure
that it is tightly stowed under the vehicle.
Push, pull, and try to turn the tire. If the
spare tire moves, tighten as necessary.
See Tire Changing 0381.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
414 Service and Maintenance
Maintenance Schedule Additional
Required Services - Severe12 000 km/7,500 mi
24 000 km/15,000 mi
36 000 km/22,500 mi
48 000 km/30,000 mi 60 000 km/37,500 mi
72 000 km/45,000 mi84 000 km/52,500 mi
96 000 km/60,000 mi
108 000 km/67,500 mi 120 000 km/75,000 mi 132 000 km/82,500 mi
144 000 km/90,000 mi 156 000 km/97,500 mi
168 000 km/105,000 mi 180 000 km/112,500 mi
192 000 km/120,000 mi 204 000 km/127,500 mi 216 000 km/135,000 mi
228 000 km/142,500 mi
240 000 km/150,000 mi
Rotate tires and perform Required Services. Check engine oil
level and oil life percentage. Change engine oil and filter,
if needed.
Check engine air filter life percentage and status. Change
engine air filter, if needed. (1)
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
Replace passenger compartment air filter. (2)@ @@@@@
Inspect evaporative control system. (3)@ @@
Replace spark plugs. Inspect spark plug wires and/or boots.
(Except 2.7L L4 Turbo Engine)@
Replace spark plugs. Inspect spark plug wires and/or boots.
(2.7L L4 Turbo Engine Only)@ @
Change automatic transmission fluid and filter.@@@
Change transfer case fluid, if equipped with 4WD. (4)@@@
Drain and fill engine cooling system. (5)@
Visually inspect accessory drive belts. (6)@
Replace brake fluid. (7)
Replace windshield wiper blades. (8)
@ @ @ @ @ @ @ @ @ @
Replace hood gas struts and tailgate dampener. (9)@ @
Replace air conditioning desiccant. (10)

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
418 Service and Maintenance
Recommended Fluids, Lubricants, and Parts
Recommended Fluids and Lubricants
This maintenance section applies to vehicles with a gasoline engine. If the vehicle has a diesel engine, see“Recommended Fluids and Lubricants”
in the Duramax diesel supplement.
Fluids and lubricants identified below by name or specification, including fluids or lubricants not listed here, can be obtained from your dealer.
Usage Fluid/Lubricant
Automatic Transmission (6-Speed Transmission) DEXRON-VI Automatic Transmission Fluid.
Automatic Transmission (8-Speed Transmission) DEXRON-HP Automatic Transmission Fluid.
Automatic Transmission (10-Speed Transmission) DEXRON ULV Automatic Transmission Fluid.
Chassis Lubrication Chassis lubricant meeting requirements of NLGI #2, Category LB or GC-LB. Engine Coolant 50/50 mixture of clean, drinkable water and use only DEX-COOL coolant. See Cooling System
0 335.
Engine Oil Engine oil meeting the dexos1 specification of the proper SAE viscosity grade. ACDelco dexos1 full synthetic is recommended. See Engine Oil0330.
Front and Rear Axle Driveshaft Splines See your dealer.
Front Axle (Four-Wheel Drive) and Rear Axle See your dealer. Hydraulic Brake System DOT 4 Hydraulic Brake Fluid. See Brake Fluid0343.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Service and Maintenance 419
UsageFluid/Lubricant
Key Lock Cylinders, Hood Hinges, Body Door Hinge Pins, Tailgate Hinge and Linkage, Fuel Door Hinge, Tailgate Handle Pivot Points, Hinges, Latch Bolt, and Linkage Multi-Purpose Lubricant, Superlube. See your dealer.
Transfer Case (Four-Wheel Drive) DEXRON-VI Automatic Transmission Fluid. Windshield Washer Automotive windshield washer fluid that meets regional freeze protection requirements.
Maintenance Replacement Parts
Replacement parts identified below by name, part number, or specification can be obtained from your dealer.
If the vehicle has a diesel engine, see the Duramax diesel supplement.
Part GM Part Number ACDelco Part Number
Engine Air Cleaner/Filter
IWith high capacity air cleaner 84121219 A3244C
IWithout high capacity air cleaner 84121217 A3246C

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./Cana-
da/Mexico-14632426) - 2021 - CRC - 11/5/20
Index 449
Assistance Program, Roadside . . . . . . . . . . . . .431
Assistance Systems for Driving . . . . . . . . . . 274
Assistance Systems for Parking andBacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
Audio Bluetooth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Auto Stop
Stop/Start System . . . . . . . . . . . . . . . . . . . . . 233
Automatic Dimming Mirrors . . . . . . . . . . . . . . . . . . . . . . . 37
Door Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Emergency Braking (AEB) . . . . . . . . . . . . . . 277
Headlamp System . . . . . . . . . . . . . . . . . . . . . 142
Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
Transmission Fluid . . . . . . . . . . . . . . . . . . . . . 333
Automatic Transmission
Manual Mode . . . . . . . . . . . . . . . . . . . . . . . . . 241
Shift Lock Control Function Check . . . . . . 347
Auxiliary Roof Mounted Lamp . . . . . . . . . . . . . . . . . . . 144
Auxiliary Jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
Avoiding Untrusted Media Devices . . . . . . . .158
Axle, Front . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346
Axle, Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346B
Battery
Exterior Lighting Battery Saver . . . . . . . . 147
Load Management . . . . . . . . . . . . . . . . . . . . . 146
Power Protection . . . . . . . . . . . . . . . . . . . . . . 147
Battery - North America . . . . . . . . . . . . .343, 391
Blade Replacement, Wiper . . . . . . . . . . . . . . . 348
Blind Spot Mirrors . . . . . . . . . . . . . . . . . . . . . . . . .37
Bluetooth Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 180, 181
Bluetooth Audio . . . . . . . . . . . . . . . . . . . . . . . . . 162
Brake Electric Boost . . . . . . . . . . . . . . . . . . . . . . . . . . 246
Parking, Electric . . . . . . . . . . . . . . . . . . . . . . . . 247
System Warning Light . . . . . . . . . . . . . . . . . . 117
Brake Pad Life System . . . . . . . . . . . . . . . . . . . 342
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .341 Antilock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
Assist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343
Pad Life System . . . . . . . . . . . . . . . . . . . . . . . 342
Braking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Automatic Emergency (AEB) . . . . . . . . . . . 277
Braking System
Front Pedestrian (FPB) . . . . . . . . . . . . . . . . . 278
Break-In, New Vehicle . . . . . . . . . . . . . . . . . . . . 228 Bulb Replacement
Center High-Mounted Stoplamp
(CHMSL) and Cargo Lamp . . . . . . . . . . . . 352
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . 350
Headlamp Aiming . . . . . . . . . . . . . . . . . . . . . . 350
Headlamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
Headlamps, Front Turn Signal, Sidemarker, and Parking Lamps . . . . . . 350
License Plate Lamps . . . . . . . . . . . . . . . . . . . 352
Taillamps, Turn Signal, Stoplamps, and Back-up Lamps . . . . . . . . . . . . . . . . . . 351
Buying New Tires . . . . . . . . . . . . . . . . . . . . . . . . 376
C
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
California Perchlorate Materials Requirements . . . 322
California Proposition 65 Warning . . . . . . . . . . . . . . . . . . .322, 343, 391, Back Cover
Canadian Vehicle Owners . . . . . . . . . . . . . . . . . . .2
Capacities and Specifications . . . . . . . . . . . . . 424
Carbon Monoxide
Engine Exhaust . . . . . . . . . . . . . . . . . . . . . . . . 238
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Winter Driving . . . . . . . . . . . . . . . . . . . . . . . . . 220
Cargo Tie-Downs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./Cana-
da/Mexico-14632426) - 2021 - CRC - 11/5/20
450 Index
Caution, Danger, and Warning . . . . . . . . . . . . . .2
Center Console Storage . . . . . . . . . . . . . . . . . . . 96
Center High-Mounted Stoplamp(CHMSL) and Cargo Lamp . . . . . . . . . . . . . . 352
Center Seat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Chains, Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
Charging Wireless . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Charging System Light . . . . . . . . . . . . . . . . . . . . 115
Check Engine Light (Malfunction Indicator) . . . . 115
Ignition Transmission Lock . . . . . . . . . . . . . 347
Child Restraints Infants and Young Children . . . . . . . . . . . . . 72
Lower Anchors and Tethers forChildren . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Older Children . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Securing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88, 92
Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Circuit Breakers . . . . . . . . . . . . . . . . . . . . . . . . . . 353
Cleaning Exterior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
Interior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
Climate Control Systems . . . . . . . . . . . . . . . . . 204 Air Conditioning . . . . . . . . . . . . . . . . . . . . . . . 204
Dual Automatic . . . . . . . . . . . . . . . . . . . . . . . . 206
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Cluster, Instrument . . . . . . . . . . . . . . . . . . . . . . 106
Collision Damage Repair . . . . . . . . . . . . . . . . . 434
Compartments
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Compass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Connected Services Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445
Connections Connected Services . . . . . . . . . . . . . . . . . . . . 446
Control Hill Descent . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
Traction and Electronic Stability . . . . . . . 248
Control Light Hill Descent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Control of a Vehicle . . . . . . . . . . . . . . . . . . . . . . 213
Controls Steering Wheel . . . . . . . . . . . . . . . . . . . . . . . . . 151
Convex Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Coolant Engine Temperature Gauge . . . . . . . . . . . . . 112
Engine Temperature Warning Light . . . . . 121
Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204, 206
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . 335
Courtesy Transportation Program . . . . . . . . 433
Coverage Explanations . . . . . . . . . . . . . . . . . . . . 175
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 Cruise Control (cont'd)
Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Cruise Control, Adaptive . . . . . . . . . . . . . . . . . 256
Cupholders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Customer Assistance . . . . . . . . . . . . . . . . . . . . . 430 Offices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
Text Telephone (TTY) Users . . . . . . . . . . . . 430
Customer Information Publications Ordering Information . . . . . 435
Customer Satisfaction Procedure . . . . . . . . . 428
Cybersecurity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
D
Damage Repair, Collision . . . . . . . . . . . . . . . . . 434
Danger, Warning, and Caution . . . . . . . . . . . . . .2
Data Collection Infotainment System . . . . . . . . . . . . . . . . . . 439
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
Data Recorders, Event . . . . . . . . . . . . . . . . . . . 438
Database Coverage Explanations . . . . . . . . . . 175
Daytime Running Lamps (DRL) . . . . . . . . . . . . 141
Defensive Driving . . . . . . . . . . . . . . . . . . . . . . . . . 213
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Destination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
Diagnostics Connected Services . . . . . . . . . . . . . . . . . . . . 447
Differential, Limited-Slip . . . . . . . . . . . . . . . . . 254
Distracted Driving . . . . . . . . . . . . . . . . . . . . . . . . . 212

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./Cana-
da/Mexico-14632426) - 2021 - CRC - 11/5/20
452 Index
F
FanEngine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340
Filter, Engine Air Cleaner . . . . . . . . . . . . . . . . . . . . . 334
Fixed Mast Antenna . . . . . . . . . . . . . . . . . . . . . .158
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Flashers, Hazard Warning . . . . . . . . . . . . . . . . .142
Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380 Changing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
FlexFuel E85 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
Floor Console Storage . . . . . . . . . . . . . . . . . . . . . 97
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405
Fluid Automatic Transmission . . . . . . . . . . . . . . . 333
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343
Four-Wheel Drive Transfer Case . . . . . . . . 242
Washer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340
Fog Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143
Folding Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Forward Collision Alert (FCA) System . . . . 275
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . 242, 346
Four-Wheel-Drive Light . . . . . . . . . . . . . . . . . . . . 118
Frequency Statement Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346 Front Fog Lamp
Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Front Pedestrian Braking (FPB) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Front Seats Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Heated and Ventilated . . . . . . . . . . . . . . . . . . 52
Fuel Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
Economy, Driving for Better . . . . . . . . . . . 212
Filling a Portable Fuel Container . . . . . . . 288
Filling the Tank . . . . . . . . . . . . . . . . . . . 285, 287
Foreign Countries . . . . . . . . . . . . . . . . . . . . . . 284
Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Low Fuel Warning Light . . . . . . . . . . . . . . . 122
Management, Active . . . . . . . . . . . . . . . . . . . 237
Prohibited Fuels . . . . . . . . . . . . . . . . . . . . . . . 284
Recommended . . . . . . . . . . . . . . . . . . . . 283, 284
Top Tier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
Full-Size Spare Tire . . . . . . . . . . . . . . . . . . . . . . . 390
Fuses Engine Compartment Fuse Block . . . . . . . 353
Fuses and Circuit Breakers . . . . . . . . . . . . . 353
Instrument Panel Fuse Block . . . . . . 357, 358
G
Garage Door Opener . . . . . . . . . . . . . . . . . . . . . 136Programming . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
Gauges Engine Coolant Temperature . . . . . . . . . . . . 112
Engine Oil Pressure . . . . . . . . . . . . . . . . . . . . . 111
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Speedometer . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Trip Odometer . . . . . . . . . . . . . . . . . . . . . . . . . 110
Voltmeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Warning Lights and Indicators . . . . . . . . . 106
General Information Service and Maintenance . . . . . . . . . . . . . . 408
Towing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
Vehicle Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
Glass Replacement . . . . . . . . . . . . . . . . . . . . . . . 348
Global Positioning System (GPS) . . . . . . . . . . 173
Glove Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
GM Mobility Reimbursement
Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .431
Guidance
Problems with the Route . . . . . . . . . . . . . . 174