GMC Sierra 3500HD 2020-2023: The Parts That Actually Wear Out

The Sierra 3500HD T1 ran from 2020-2023 and is dually, gooseneck, and max tow. After enough of these come across the parts counter you start to see the same short list of components over and over. Here is what owners of this generation actually end up buying, and what to know before you order.

Sensors, Cameras and Driver Assistance

The usual tell is a backup camera image that flickers, goes blue, or shows lines. This is one of the items where a towing or work truck and a commuter diverge sharply.

Common parts in this group: park assist sensors, backup cameras, blind zone modules, front camera modules, radar sensors.

Worth knowing: These are calibrated devices, and the calibration lives in the module that expects a specific sensor.

Exhaust and Emissions

The usual tell is a diesel that regenerates far more often than it used to. This is one of the items where a towing or work truck and a commuter diverge sharply.

Common parts in this group: catalytic converters, oxygen sensors, DEF injectors, diesel particulate filters, EVAP purge valves.

Worth knowing: Catalytic converters are emissions-certified parts, and substrate loading is what the downstream oxygen sensor is judging.

Suspension

The usual tell is a ride height that sits lower on one corner. Heat is the accelerant on this one, which is why it shows up faster here than up north.

Common parts in this group: shocks, struts, control arms, ball joints, sway bar links.

Worth knowing: Vehicles with adaptive or air suspension talk to the module, and non-OEM parts often will not report correctly.

Heating and Air Conditioning

The usual tell is a musty smell for the first thirty seconds after startup. The number in the manual assumes conditions most people in North Texas do not have.

Common parts in this group: cabin air filters, blower motors, blower motor resistors, A/C compressors, condensers.

Worth knowing: Condenser and evaporator core dimensions are specific, and a near-fit leaks at the seal.

Interior

The usual tell is a sun visor that will not stay up. The number in the manual assumes conditions most people in North Texas do not have.

Common parts in this group: floor liners, carpet floor mats, console lids, seat covers, shift knobs.

Worth knowing: Genuine trim matches grain and color code, which universal parts never quite do.

Cooling System

The usual tell is crusty orange residue around a hose clamp or the surge tank seam. Owners who do mostly short trips see this sooner than the mileage suggests.

Common parts in this group: radiators, water pumps, thermostats, coolant hoses, cooling fans.

Worth knowing: Aftermarket radiators frequently use fewer rows or thinner tanks than the original, which shows up as a heat problem only when you tow.

Before You Order

Have the VIN ready. On a Sierra 3500HD the same model year can carry two or three different engines and several suspension packages.
Check the SPID label in the glove box or console for your RPO codes.
Front and rear parts are rarely the same number, even when they look identical.
If the part is electrical, confirm the fit before you order. Electrical parts are not returnable at any GM dealer, including us.

Ordering is easiest if you have the VIN in front of you. Head to our GMC OEM parts catalog to shop by vehicle, or search for Sierra 3500HD parts to go straight to a part.