Owner’s manual specs

2021 GMC Sierra Specs: Fluids, Maintenance Schedule & Fuse Box

Figures for the 2021 GMC Sierra, copied from GMC’s own owner’s manual. Every one links to the manual page it came from.

From the manufacturer’s manuals. Every figure here is copied from the manufacturer's own manual, with a link to the page it came from. Where a manual is unclear or contradicts itself, we leave the figure out.

Fluids & capacities

Automatic Transmission (6-Speed Transmission)

DEXRON-VI Automatic Transmission Fluid.

Applies to: Automatic Transmission (6-Speed Transmission)

Source: 2021 GMC Sierra Owner Manual, page 431

Automatic Transmission (8-Speed Transmission)

DEXRON-HP Automatic Transmission Fluid.

Applies to: Automatic Transmission (8-Speed Transmission)

Source: 2021 GMC Sierra Owner Manual, page 431

Maintenance schedule

Normal service schedule

Use this for ordinary driving.

Service	When
Replace passenger compartment air filter. (2) Source: 2021 GMC Sierra Denali 2500HD and 3500HD Owner Manual, page 393	Every 22,500 mi(36,000 km)

Severe service schedule

Use this if you tow, idle a lot, drive short trips in the cold, or run in dust.

Service	When
Change automatic transmission fluid and filter. Source: 2021 GMC Sierra Denali 2500HD and 3500HD Owner Manual, page 395	Every 45,000 mi(72,000 km)
Replace passenger compartment air filter. (2) Source: 2021 GMC Sierra Denali 2500HD and 3500HD Owner Manual, page 395	Every 22,500 mi(36,000 km)

Fuse box locations & fuse chart

Engine Compartment Fuse Block

What each fuse protects

Fuse	Amps	Protects	Source
1	—	High-beam left	p.336
2	—	High-beam right	p.362
3	—	Headlamp left	p.336
4	—	Headlamp right	p.362
5	—	Headlamp	p.338
8	—	Fog lamp	p.336
11	—	Police upfitter	p.336
13	—	Washer front	p.336
14	—	Washer rear	p.336
17	—	IECL 1	p.336
18	—	DC/AC inverter	p.338
19	—	DC/AC inverter	p.336
20	—	IECR 2 (LD) / EBCM2 (HD)	p.336
22	—	IECL 2	p.336
23	—	Rear window defogger	p.338
24	—	EBCM 1	p.336
27	—	Horn	p.337
32	—	Rear window defogger	p.337
33	—	Heated mirror	p.337
34	—	Parking lamp left	p.337
35	—	Parking lamp	p.338
36	—	Run/Crank	p.338
40	—	Misc ignition	p.337
41	—	Trailer parking lamp	p.337
42	—	Park lamp right	p.337
46	—	Engine control module ignition	p.337
47	—	Transmission control module ignition	p.363
49	—	Transmission control module	p.337
50	—	A/C clutch	p.337
51	—	Transfer case control module	p.337
52	—	Front wiper	p.337
53	—	Center high-mounted stop lamp	p.337
54	—	Trailer reverse lamp	p.337
55	—	Trailer back-up lamp	p.337
56	—	SADS	p.337
57	—	TTPM/SBZA	p.337
58	—	Starter motor (LD & HD DSL)	p.337
59	—	A/C clutch	p.338
60	—	Active fuel management 1	p.337
61	—	VES	p.337
62	—	Integrated chassis control module/CVS	p.337
63	—	Trailer battery	p.363
64	—	Starter Motor (LD & HD DSL)	p.338
65	—	Auxiliary underhood electrical center	p.337
66	—	Cooling fan motor left	p.337
67	—	Active fuel management 2	p.337
69	—	Starter Pinion (LD) / Starter Motor (HD Gas)	p.337
70	—	Starter Pinion (LD) / Starter Motor (HD Gas)	p.338
71	—	Cooling fan	p.337
73	—	Trailer stop/turn lamp left	p.337
74	—	Trailer Interface Module 1	p.337
75	—	DEFC	p.337
76	—	Electric RNG BDS	p.337
77	—	Powertrain	p.338
78	—	Engine control module	p.337
79	—	Auxiliary battery	p.337
80	—	Cabin cooling pump	p.337
82	—	Trailer Interface Module 2	p.338
83	—	FTZM	p.338
84	—	Trailer brake	p.338
85	—	ENG	p.338
86	—	Engine control module	p.338
87	—	Injector B even	p.338
88	—	O2 B sensor	p.338
89	—	O2 A sensor	p.338
90	—	Injector A odd	p.338
91	—	Engine control module throttle control	p.338