Specifications Comparison: 2023 GMC Sierra 3500 vs 2021 GMC Sierra 3500

Legroom

Trim	Eng.	Drive train	1st Row Legroom (in)	2nd Row Legroom (in)
HD Pro Crew Cab 159"	6.6L V8	RWD	44	43
HD Pro Crew Cab 172"	6.6L V8	RWD	44	43
HD Pro Double Cab 162"	6.6L V8	RWD	44	35
HD Pro Reg Cab 142"	6.6L V8	RWD	44
HD Pro Crew Cab 159"	6.6L V8	4WD	44	43
HD Pro Crew Cab 172"	6.6L V8	4WD	44	43
HD Pro Double Cab 162"	6.6L V8	4WD	44	35
HD Pro Reg Cab 142"	6.6L V8	4WD	44
HD SLE Crew Cab 159"	6.6L V8	RWD	44	43
HD SLE Crew Cab 172"	6.6L V8	RWD	44	43
HD SLE Double Cab 162"	6.6L V8	RWD	44	35
HD SLE Reg Cab 142"	6.6L V8	RWD	44
HD SLE Crew Cab 159"	6.6L V8	4WD	44	43
HD SLE Crew Cab 172"	6.6L V8	4WD	44	43
HD SLE Double Cab 162"	6.6L V8	4WD	44	35
HD SLE Reg Cab 142"	6.6L V8	4WD	44
HD SLT Crew Cab 159"	6.6L V8	RWD	44	43
HD SLT Crew Cab 172"	6.6L V8	RWD	44	43
HD SLT Crew Cab 159"	6.6L V8	4WD	44	43
HD SLT Crew Cab 172"	6.6L V8	4WD	44	43
HD AT4 Crew Cab 159"	6.6L V8	4WD	44	43
HD AT4 Crew Cab 172"	6.6L V8	4WD	44	43
HD Denali Crew Cab 159"	6.6L V8	4WD	44	43
HD Denali Crew Cab 172"	6.6L V8	4WD	44	43

Trim	Eng.	Drive train	1st Row Legroom (in)	2nd Row Legroom (in)
HD Crew Cab	6.6L V8	RWD	44	43
HD Crew Cab	6.6L V8	RWD	44	43
HD Crew Cab	6.6L V8	4WD	44	43
HD Crew Cab	6.6L V8	4WD	44	43
HD Crew Cab AT4	6.6L V8	4WD	44	43
HD Crew Cab AT4	6.6L V8	4WD	44	43
HD Crew Cab Denali	6.6L V8	4WD	44	43
HD Crew Cab Denali	6.6L V8	4WD	44	43
HD Crew Cab SLE	6.6L V8	RWD	44	43
HD Crew Cab SLE	6.6L V8	RWD	44	43
HD Crew Cab SLE	6.6L V8	4WD	44	43
HD Crew Cab SLE	6.6L V8	4WD	44	43
HD Crew Cab SLT	6.6L V8	RWD	44	43
HD Crew Cab SLT	6.6L V8	RWD	44	43
HD Crew Cab SLT	6.6L V8	4WD	44	43
HD Crew Cab SLT	6.6L V8	4WD	44	43
HD Extended Cab	6.6L V8	RWD	44	35
HD Extended Cab	6.6L V8	RWD	44	35
HD Extended Cab	6.6L V8	4WD	44	35
HD Extended Cab	6.6L V8	4WD	44	35
HD Extended Cab SLE	6.6L V8	RWD	44	35
HD Extended Cab SLE	6.6L V8	RWD	44	35
HD Extended Cab SLE	6.6L V8	4WD	44	35
HD Extended Cab SLE	6.6L V8	4WD	44	35
HD Regular Cab	6.6L V8	RWD	44
HD Regular Cab	6.6L V8	RWD	44
HD Regular Cab	6.6L V8	4WD	44
HD Regular Cab	6.6L V8	4WD	44
HD Regular Cab SLE	6.6L V8	RWD	44
HD Regular Cab SLE	6.6L V8	RWD	44
HD Regular Cab SLE	6.6L V8	4WD	44
HD Regular Cab SLE	6.6L V8	4WD	44

Trim	Eng.	Drive train	1st Row Legroom (cm)	2nd Row Legroom (cm)
HD Pro Crew Cab 159"	6.6L V8	RWD	111	109
HD Pro Crew Cab 172"	6.6L V8	RWD	111	109
HD Pro Double Cab 162"	6.6L V8	RWD	111	88
HD Pro Reg Cab 142"	6.6L V8	RWD	111
HD Pro Crew Cab 159"	6.6L V8	4WD	111	109
HD Pro Crew Cab 172"	6.6L V8	4WD	111	109
HD Pro Double Cab 162"	6.6L V8	4WD	111	88
HD Pro Reg Cab 142"	6.6L V8	4WD	111
HD SLE Crew Cab 159"	6.6L V8	RWD	111	109
HD SLE Crew Cab 172"	6.6L V8	RWD	111	109
HD SLE Double Cab 162"	6.6L V8	RWD	111	88
HD SLE Reg Cab 142"	6.6L V8	RWD	111
HD SLE Crew Cab 159"	6.6L V8	4WD	111	109
HD SLE Crew Cab 172"	6.6L V8	4WD	111	109
HD SLE Double Cab 162"	6.6L V8	4WD	111	88
HD SLE Reg Cab 142"	6.6L V8	4WD	111
HD SLT Crew Cab 159"	6.6L V8	RWD	111	109
HD SLT Crew Cab 172"	6.6L V8	RWD	111	109
HD SLT Crew Cab 159"	6.6L V8	4WD	111	109
HD SLT Crew Cab 172"	6.6L V8	4WD	111	109
HD AT4 Crew Cab 159"	6.6L V8	4WD	111	109
HD AT4 Crew Cab 172"	6.6L V8	4WD	111	109
HD Denali Crew Cab 159"	6.6L V8	4WD	111	109
HD Denali Crew Cab 172"	6.6L V8	4WD	111	109

Trim	Eng.	Drive train	1st Row Legroom (cm)	2nd Row Legroom (cm)
HD Crew Cab	6.6L V8	RWD	111	109
HD Crew Cab	6.6L V8	RWD	111	109
HD Crew Cab	6.6L V8	4WD	111	109
HD Crew Cab	6.6L V8	4WD	111	109
HD Crew Cab AT4	6.6L V8	4WD	111	109
HD Crew Cab AT4	6.6L V8	4WD	111	109
HD Crew Cab Denali	6.6L V8	4WD	111	109
HD Crew Cab Denali	6.6L V8	4WD	111	109
HD Crew Cab SLE	6.6L V8	RWD	111	109
HD Crew Cab SLE	6.6L V8	RWD	111	109
HD Crew Cab SLE	6.6L V8	4WD	111	109
HD Crew Cab SLE	6.6L V8	4WD	111	109
HD Crew Cab SLT	6.6L V8	RWD	111	109
HD Crew Cab SLT	6.6L V8	RWD	111	109
HD Crew Cab SLT	6.6L V8	4WD	111	109
HD Crew Cab SLT	6.6L V8	4WD	111	109
HD Extended Cab	6.6L V8	RWD	111	88
HD Extended Cab	6.6L V8	RWD	111	88
HD Extended Cab	6.6L V8	4WD	111	88
HD Extended Cab	6.6L V8	4WD	111	88
HD Extended Cab SLE	6.6L V8	RWD	111	88
HD Extended Cab SLE	6.6L V8	RWD	111	88
HD Extended Cab SLE	6.6L V8	4WD	111	88
HD Extended Cab SLE	6.6L V8	4WD	111	88
HD Regular Cab	6.6L V8	RWD	111
HD Regular Cab	6.6L V8	RWD	111
HD Regular Cab	6.6L V8	4WD	111
HD Regular Cab	6.6L V8	4WD	111
HD Regular Cab SLE	6.6L V8	RWD	111
HD Regular Cab SLE	6.6L V8	RWD	111
HD Regular Cab SLE	6.6L V8	4WD	111
HD Regular Cab SLE	6.6L V8	4WD	111