2021 GMC Sierra 3500 Drivetrain Parts

This table covers the actuators that engage four-wheel drive at the transfer case or axle. Typical signs include a door or range that will not move, or a click with no motion. Confirm the command signal before replacing the actuator — a failed module looks the same. Read more

2 4WD Actuator parts for the 2021 GMC Sierra 3500 come from 2 brands — AAM and GM GENUINE.

Part numbers include AAM 40190486 and GM GENUINE 85739453.

This table covers the 4WD Actuator Clutch shafts. Read more

One part is listed for the 2021 GMC Sierra 3500 — GM GENUINE 84756929.

This table covers the 4WD Actuator Clutch sleeves. Read more

One part is listed for the 2021 GMC Sierra 3500 — GM GENUINE 86540180.

This table covers the 4WD Actuator Clutch Sleeve shims. Read more

6 4WD Actuator Clutch Sleeve Shim parts for the 2021 GMC Sierra 3500 come from GM GENUINE. The "Popular" part is GM GENUINE 15522141.

Part numbers include GM GENUINE 15522141, GM GENUINE 15522140 and GM GENUINE 15522142, among others listed above.

This table covers the forks a 4WD actuator moves. Read more

This group shows a single part: GM GENUINE 12479213.

This table covers the 4WD Actuator housings. Read more

One part is listed for the 2021 GMC Sierra 3500 — GM GENUINE 84368173.

This table covers the Axle / Differential assemblies. Read more

3 Axle / Differential Assembly parts for the 2021 GMC Sierra 3500 come from GM GENUINE.

This group includes GM GENUINE 84989575, GM GENUINE 84989576 and GM GENUINE 85819587.

This table covers the Axle bolts. Read more

2 Axle Bolt parts are listed for the 2021 GMC Sierra 3500, from AAM and GM GENUINE.

Listed part numbers: AAM 40023476 and GM GENUINE 20920619.

This table covers the Axle Hub keys. Read more

This group shows a single part: GM GENUINE 22760462.

This table covers the Axle shafts. Read more

9 Axle Shaft parts for the 2021 GMC Sierra 3500 come from 2 brands — AAM and GM GENUINE. The "Popular" part is AAM 40223780.

Part numbers include AAM 40223780, AAM 40175943 and AAM 40223783, among others listed above.

This table covers the Axle Shaft bearings. Typical signs include a growl that rises with speed, or play in the shaft or hub. Set preload the way the notes specify. A dry or crushed bearing fails quickly. Read more

This group shows a single part: GM GENUINE FD100.

This table covers the gaskets that seal the Axle Shaft Flange. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

5 Axle Shaft Flange Gasket parts for the 2021 GMC Sierra 3500 come from 3 brands — DORMAN, GM GENUINE and FEL-PRO. The "Popular" part is DORMAN 926573.

Part numbers include DORMAN 926573, DORMAN 926878 and FEL-PRO 55487, among others listed above.

This table covers the Axle Shaft Lock / Snap rings. Read more

This group shows a single part: GM GENUINE 11603383.

This table covers the Axle Shaft Pilot bearings. Typical signs include a growl that rises with speed, or play in the shaft or hub. Set preload the way the notes specify. A dry or crushed bearing fails quickly. Read more

This group shows a single part: GM GENUINE RW203.

This table covers the seals where an axle shaft exits the housing. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

GM GENUINE supplies the 3 Axle Shaft Seal parts for the 2021 GMC Sierra 3500.

Listed part numbers: GM GENUINE 84756933, GM GENUINE 291366 and GM GENUINE 291336.

This table covers the Axle Vent valves. Typical signs include a circuit that will not hold, a whistle, or a code for this valve. A stuck valve is often debris. Clean the ports before installing the new one. Read more

One part is listed for the 2021 GMC Sierra 3500 — GM GENUINE 26063647.

This table covers the complete CV axle shafts from differential (or hub) to wheel. Typical signs include a click in tight turns, grease flung around the wheel well, or a vibration that builds with speed. A torn boot caught early is a boot kit; caught late it is the whole axle. Torque the axle nut to the method in the notes. Read more

4 CV Axle parts are listed for the 2021 GMC Sierra 3500, from GM GENUINE, GSP, TOP NOTCH and 1 other brand.

Part numbers include GM GENUINE 85838011, GSP NCV10226 and TOP NOTCH TN20360, among others listed above.

This table covers the boots that keep grease in a CV joint. Typical signs include a split boot, grease flung around the joint, or a click once grit is inside. A boot caught early is a kit. Once the joint has clicked, the joint itself is usually worn. Read more

GM GENUINE supplies both parts for the 2021 GMC Sierra 3500.

Listed part numbers: GM GENUINE 15898093 and GM GENUINE 84534724.

This table covers the bands that clamp a CV boot to the joint. Read more

3 CV Joint Boot Band parts for the 2021 GMC Sierra 3500 come from GM GENUINE.

This group includes GM GENUINE 11603325, GM GENUINE 07849175 and GM GENUINE 11603324.

This table covers the CV Joint Lock rings. Read more

This group shows a single part: GM GENUINE 11603382.

This table covers the adjusters that set differential bearing preload. Read more

GM GENUINE supplies both parts for the 2021 GMC Sierra 3500.

Part numbers include GM GENUINE 84850193 and GM GENUINE 84031696.

This table covers the Differential Bearing Adjuster Nut locks. Read more

GM GENUINE supplies both parts for the 2021 GMC Sierra 3500.

This group includes GM GENUINE 85123912 and GM GENUINE 20768583.

This table covers the Differential Bearing Adjuster Nut Lock bolts. Read more

2 Differential Bearing Adjuster Nut Lock Bolt parts for the 2021 GMC Sierra 3500 come from 2 brands — AAM and GM GENUINE.

Part numbers include AAM 40181318 and GM GENUINE 11603333.

This table covers the carriers that hold the differential gears in the axle. Read more

3 Differential Carrier parts are listed for the 2021 GMC Sierra 3500, from AAM and GM GENUINE.

Listed part numbers: AAM 40186599, AAM 40099548 and GM GENUINE 84756918.

This table covers the bearings and races that support the differential carrier. Read more

GM GENUINE supplies both parts for the 2021 GMC Sierra 3500.

Listed part numbers: GM GENUINE 84678054 and GM GENUINE 84757382.

This table covers the Differential Carrier bolts. Read more

4 Differential Carrier Bolt parts for the 2021 GMC Sierra 3500 come from GM GENUINE.

Listed part numbers: GM GENUINE 11571088, GM GENUINE 11571087 and GM GENUINE 11549337, plus the other parts above.

This table covers the Differential Carrier shims. Read more

5 Differential Carrier Shim parts for the 2021 GMC Sierra 3500 come from GM GENUINE.

Listed part numbers: GM GENUINE 12471547, GM GENUINE 12471548 and GM GENUINE 12471549, plus the other parts above.

This table covers the clutch packs in a limited-slip or locking differential. Read more

One part is listed for the 2021 GMC Sierra 3500 — GM GENUINE 84575960.

This table covers the Differential Clutch Pack clips. Read more

One part is listed for the 2021 GMC Sierra 3500 — GM GENUINE 00462787.

This table covers the Differential covers. Read more

This group shows a single part: GM GENUINE 84757353.

This table covers the Differential Cover bolts. Read more

3 Differential Cover Bolt parts are listed for the 2021 GMC Sierra 3500, from AAM and GM GENUINE.

Part numbers include AAM 4000216910, AAM 40002169 and GM GENUINE 12471307.

This table covers the gaskets that seal the Differential Cover. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

GM GENUINE supplies the 3 Differential Cover Gasket parts for the 2021 GMC Sierra 3500.

This group includes GM GENUINE 84756927, GM GENUINE 85736736 and GM GENUINE 85742563.

This table covers the Differential Cross pins. Read more

2 Differential Cross Pin parts for the 2021 GMC Sierra 3500 come from GM GENUINE.

Listed part numbers: GM GENUINE 84990314 and GM GENUINE 85099031.

This table covers the Differential Crush sleeves. Read more

This group shows a single part: AAM 40099601.

This table covers the Differential Fill drain plugs. Read more

4 Differential Fill / Drain Plug parts are listed for the 2021 GMC Sierra 3500, from AAM and GM GENUINE.

Listed part numbers: AAM 40042937, AAM 40007601 and GM GENUINE 55573646, plus the other parts above.

This table covers the Differential Lock actuators. Typical signs include a door or range that will not move, or a click with no motion. Confirm the command signal before replacing the actuator — a failed module looks the same. Read more

One part is listed for the 2021 GMC Sierra 3500 — GM GENUINE 12471543.

This table covers the Differential Lock plates. Typical signs include warpage, cracks, or a plate that no longer locates the assembly. Confirm which plate the notes describe — backing plates, clutch plates and strike plates are different parts. Read more

This group shows a single part: GM GENUINE 22828388.

This table covers the thrust blocks in a locking differential. Read more

GM GENUINE supplies the 5 Differential Lock Thrust Block parts for the 2021 GMC Sierra 3500.

This group includes GM GENUINE 12471567, GM GENUINE 12471568 and GM GENUINE 12471569 and the remaining parts above.

This table covers the brackets that mount the Differential Mount. Typical signs include a cracked mount, a rattle, or a bracket that no longer holds alignment. Confirm position in the notes. Many brackets look alike and bolt to different corners. Read more

2 Differential Mount Bracket parts for the 2021 GMC Sierra 3500 come from GM GENUINE.

Part numbers include GM GENUINE 86787382 and GM GENUINE 86787381.

This table covers the bearings and races on the differential pinion. Read more

5 Differential Pinion Bearing / Race parts for the 2021 GMC Sierra 3500 come from 2 brands — GM GENUINE and AAM. The "Popular" part is GM GENUINE 84757358.

Part numbers include GM GENUINE 84757358, AAM 40265294 and GM GENUINE 84446306, among others listed above.

This table covers the baffles that control oil at the pinion bearings. Read more

This group shows a single part: GM GENUINE 84757349.

This table covers the flanges that connect the driveshaft to the differential pinion. Read more

3 Differential Pinion Flange parts are listed for the 2021 GMC Sierra 3500, from AAM and GM GENUINE.

Part numbers include AAM 40208236, AAM 40224929 and GM GENUINE 84679952.

This table covers the Differential Pinion nuts. Read more

3 Differential Pinion Nut parts are listed for the 2021 GMC Sierra 3500, from GM GENUINE and AAM.

Part numbers include AAM 40169206, GM GENUINE 84757406 and GM GENUINE 11603375.

This table covers the wear sleeves used to restore a grooved pinion seal surface. Read more

One part is listed for the 2021 GMC Sierra 3500 — AAM 26060977.

This table covers the seals at the differential pinion yoke. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

5 Differential Pinion Seal parts are listed for the 2021 GMC Sierra 3500, from AAM, TIMKEN and GM GENUINE. GM GENUINE 84757357 carries the "Popular" badge.

Part numbers include GM GENUINE 84757357, AAM 40189030 and AAM 40255188, among others listed above.

This table covers the Differential Pinion Shaft Lock bolts. Read more

This group shows a single part: GM GENUINE 12479059.

This table covers kits that group the bearings, races and seals for a differential rebuild. Read more

3 Differential Rebuild Kit parts for the 2021 GMC Sierra 3500 come from 2 brands — AAM and USA STANDARD GEAR.

The Master Kit section lists 1 option from USA STANDARD GEAR — grouped under the catalog's "Master Kit" designation — the notes column spells out what sets them apart. USA STANDARD GEAR USA12848 is listed in this group.

In the Standard Kit grade, AAM supplies 1 part: grouped under the catalog's "Standard Kit" designation — the notes column spells out what sets them apart. A representative part number is AAM 74067028.

1 further part sits outside the graded sections, with the same engine-level match.

Part numbers include USA STANDARD GEAR USA12848, AAM 74067028 and AAM 74067032.

This table covers the ring-and-pinion gear sets that set the axle ratio. Read more

8 Differential Ring and Pinion parts are listed for the 2021 GMC Sierra 3500, from AAM and GM GENUINE. AAM 115T1373GK carries the "Popular" badge.

Part numbers include AAM 115T1373GK, AAM 925T1373GK and AAM 120T1342GEARKIT, among others listed above.

This table covers the Differential Ring Gear bolts. Read more

4 Differential Ring Gear Bolt parts are listed for the 2021 GMC Sierra 3500, from AAM and GM GENUINE.

This group includes AAM 26064505, AAM 40022812 and GM GENUINE 11546991 and the remaining parts above.

This table covers the seals at the Differential. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again. Read more

This group shows a single part: AAM 26064030.

This table covers the Differential Spider gears. Read more

One part is listed for the 2021 GMC Sierra 3500 — GM GENUINE 85099032.

This table covers the Differential washers. Read more

One part is listed for the 2021 GMC Sierra 3500 — GM GENUINE 12471564.

This table covers the driveshafts that carry torque from the transmission or transfer case. Read more

9 Drive Shaft parts for the 2021 GMC Sierra 3500 come from 3 brands — GM GENUINE, DORMAN and TRAKMOTIVE. The "Popular" part is GM GENUINE 87821417.

This group includes GM GENUINE 87821417, GM GENUINE 87828755 and DORMAN 966487 and the remaining parts above.

This table covers the Drive Shaft bolts. Read more

GM GENUINE supplies both parts for the 2021 GMC Sierra 3500.

Listed part numbers: GM GENUINE 11548472 and GM GENUINE 11602575.

This table covers the Drive Shaft Center Support bearings. Typical signs include a growl that rises with speed, or play in the shaft or hub. Set preload the way the notes specify. A dry or crushed bearing fails quickly. Read more

9 Drive Shaft Center Support Bearing parts for the 2021 GMC Sierra 3500 come from 4 brands — ANCHOR, DEA / MARMON RIDE CONTROL, WESTAR and 1 other brand. The "Popular" part is ANCHOR 6153.

The Economy section lists 4 options from DEA / MARMON RIDE CONTROL and WESTAR — the catalog's value-priced group. DEA / MARMON RIDE CONTROL A60176 is listed in this group.

In the Standard Replacement grade, ANCHOR and GM GENUINE supply 5 parts: built to original-equipment specification. A representative part number is ANCHOR 6153.

Part numbers include ANCHOR 6153, DEA / MARMON RIDE CONTROL A60176 and DEA / MARMON RIDE CONTROL A60180, among others listed above.

This table covers the Drive Shaft End yokes. Read more

2 Drive Shaft End Yoke parts are listed for the 2021 GMC Sierra 3500, from GM GENUINE and USA STANDARD GEAR.

Part numbers include GM GENUINE 85111015 and USA STANDARD GEAR USA41204.

This table covers the Drive Shaft Flange yokes. Read more

One part is listed for the 2021 GMC Sierra 3500 — AAM 40145239.

This table covers the Drive Shaft retainers. Read more

2 Drive Shaft Retainer parts for the 2021 GMC Sierra 3500 come from GM GENUINE.

Listed part numbers: GM GENUINE 23107857 and GM GENUINE 23170499.

This table covers the Drive Shaft Slip yokes. Read more

4 Drive Shaft Slip Yoke parts for the 2021 GMC Sierra 3500 come from GM GENUINE.

Part numbers include GM GENUINE 84620581, GM GENUINE 84679953 and GM GENUINE 84679954, among others listed above.

This table covers the gear oils specified for the axle or transfer case. Typical signs include a low-oil lamp, knocking, or oil that has gone thin before the next interval. Match the viscosity and spec in the notes, not just the weight on the bottle. Read more

8 Gear Oil parts are listed for the 2021 GMC Sierra 3500, from VALVOLINE and ACDELCO. VALVOLINE VV820 carries the "Popular" badge.

In the SAE 75W-85 grade, ACDELCO supplies 1 part: grouped under the catalog's "SAE 75W-85" designation — the notes column spells out what sets them apart. A representative part number is ACDELCO 104091.

In the SAE 75W-90 grade, VALVOLINE and ACDELCO supply 7 parts: grouped under the catalog's "SAE 75W-90" designation — the notes column spells out what sets them apart. A representative part number is VALVOLINE VV820.

This group includes VALVOLINE VV820, ACDELCO 104091 and VALVOLINE VV975 and the remaining parts above.

This table covers the gaskets that seal the Power Take Off (PTO). Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for. Read more

This group shows a single part: GM GENUINE 24297155.