Does the 2019-2021 GMC Sierra 1500 have transmission shifting problems?
Yes, 2019-2021 Sierra 1500 models can exhibit harsh, jerky, or delayed shifts from the 10-speed automatic transmission. GM addressed the condition with technical service bulletins and PCM software updates, so a software reflash is the typical fix rather than a full hardware replacement. If you are inspecting one, check service records for an updated PCM calibration. When left unaddressed, the main consequence is poor drivability rather than immediate catastrophic failure.