2024+ GMC Duramax L5P Parts & Upgrades

What 2024 changed on the Sierra HD

Two things happened at once. The truck got a refresh: new front fascia and bumper, LED projector headlamps with an animated approach-lighting sequence, a 13.4-inch center screen and 12.3-inch driver display on the upper trims, and the AT4X joined the lineup with Multimatic DSSV dampers, 35-inch tires and extra skid plates. The engine got a revision at the same time. The 6.6L V8 went from 445 hp and 910 lb-ft to 470 and 975 with up to 25 percent more low-end torque, which GM credits to the control architecture, the combustion system and the turbocharger, and which aftermarket sources tie to revised pistons, revised injectors, a different turbo and the E42 module on GM's Global B electrical architecture. Underneath, the Denso HP4 pump feeds eight Denso G4S solenoid injectors at up to 29,000 psi, the electrically actuated BorgWarner variable-geometry turbo in the valley also serves as the exhaust brake, and the Allison-branded 10L1000 ten-speed became standard behind both engines. Towing picked up Adaptive Cruise Control with Trailer, Enhanced Transparent Trailer for fifth-wheel and gooseneck, Trailer Side Blind Zone Alert and a GCW Alert. Background on the engine family is on the Duramax hub.

What fails and why

Sierra HD owners have been loud about a short list of things, and GM has bulletins out on most of them.

• Steering. Recall 23V-549 covers 2024 Sierra 2500 and 3500 steering gear shafts that can fracture and separate from the steering arm; the dealer inspection and replacement are free, so confirm completion by VIN first. Separate from that, Sierra owners report intermittent heavy steering and wander needing repeated alignments around 13,000 miles.
• Transmission valve body. Harsh downshift, rear-wheel lock-up at speed, limp mode and delayed engagement are a leading 2024 Sierra 2500 complaint theme, with stated mileages from 6,000 to 83,000 and 60 to 90 day parts backorders. GM covered 10L1000 valve body repair in a September 2025 technician seminar.
• Oil cooler. Bulletin 25-NA-150 blames damaged oil cooler seals, not the cooler, for oil seeping at the cooler on 2024-2026 trucks. Owner reports include a cooler that let go twice within five miles of the repair and a Denali Ultimate down 52 days waiting on a backordered part.
• Electrical connections. Multiple glow plug codes at once come from a Battery Distribution Unit fuse making intermittent contact or bent terminals in the X950D 55-way engine harness connector. High resistance at the G103A and G103B body grounds under the hood throws CAN bus errors, a dash full of lights and loss of EBCM communication.
• Front lighting. Headlamps, daytime running lamps, parking lamps or turn signals can cut out and come back after an ignition cycle because the Multi-purpose LED Driver inside the lamp fails; some 2025 Sierra lamps also have soldering defects identified by Julian date.
• Brakes and trailer braking. 2024 Sierra HD owners report pad wear warnings before 25,000 miles, and intermittent loss of trailer braking from the integrated controller shows up across these trucks, including a Sierra fifth-wheel report at about 30,000 miles.
• Dual tanks. On 3500HD trucks with two tanks the gauge can drop to empty while the ECM still reads most of a tank. The cause is a blocked transfer inlet port in the front tank sender, and the fix is a new sender, air-tested below 5 psi before it goes in.
• Tires. Reports on 2024 Sierra HD include a front tire rupture at highway speed on tires with 50,000 miles and 18-inch all-terrains out of round at about 25,000.

Stock replacement vs. upgrade

A Sierra HD that tows for a living mostly needs fluids and filters on time. Chassis fuel filter ACDelco TP1015 at 22,500 miles, engine air filter element A3248C at 45,000 miles or four years, Dexron ULV in the 10L1000 with the external spin-on filter at 45,000 and the internal filter at 97,500, Dexron VI in the transfer case at 45,000. Differential fluid is not on the factory schedule; 30,000 to 60,000 miles is the common recommendation on trucks that pull. That matters because long-distance towing at GVWR drives transmission temperatures that accelerate clutch wear, and converter shudder on hot fluid comes out of worn friction material, unstable lockup pressure, valve body wear or degraded fluid. Fresh fluid and updated factory TCM software come before condemning a converter.

For more capability, the compliant choices are documented. Banks offers a 5-inch stainless DPF-back for 2024-2026 single-rear-wheel trucks, claiming 192 percent more flow area, 85 percent less backpressure and a 15 percent cooler tailpipe during regeneration, with chrome or Cerakote tips; aFe lists a 5-inch 409 stainless DPF-back for 2024 and later as well. On intakes, Banks catalogs one kit for 2024 and a separate kit for 2025-2026 with the crankcase-ventilation sensor accommodation, and describes them as compliant without publishing EO numbers, so confirm California eligibility before you order into that state. Banks also describes its Derringer HO piggyback as 50-state emissions legal for 2024-2026 with a claimed 86 hp and 178 lb-ft and no ECM reflash, and bundles it with a PedalMonster throttle controller, Monster-Ram turbo inlet, boost tubes and an iDash Pro. If you add power, plan for the transmission: built 10L1000 units add clutch capacity, refined valve body line pressure and better seals, and triple-disc billet converters bring about 33 percent more apply area with higher-friction material.

What we carry

Service and fluid coverage comes from Hot Shot's Secret and Lucas Oil in CK-4 engine oils and fuel additives, with ACDelco oil filters and coated Gold rotors and water separator filters from FASS. For the towing end there are B&W Trailer Hitches hitches and Air Lift air spring hardware, plus BDS Suspension heavy-duty tie rod kits. Pacific Performance Engineering covers steering and oiling with forged XR tie rod kits, drilled 7/8-inch steering assemblies, oversized and high-efficiency oil filters, billet filter sockets and fuel coolant pump relocation kits. Wehrli Custom Fabrication handles the cooling and exhaust-side hardware: thermostat housings, upper coolant pipe kits, auxiliary coolant tanks, low coolant level sensors, billet exhaust manifold and stainless up-pipe kits, up-pipe bolt kits and AAM rear differential covers. MBRP supplies stainless and aluminized exhaust components, mufflers and resonators, and Mishimoto adds cooling parts. For gauges and data there are Edge Products monitors, EGT and pressure sensor kits and A-pillar mounts alongside Banks Power turbo inlet elbows and boost tube kits, with injector connectors and fuel-side parts from Fleece Performance and Exergy, and tooling and hardware from XDP MFG.

Fitment notes

Check the year, the trim and the rear wheels before you buy. Monitors and tuners split hard at 2024 because of the E42 and Global B change, and Banks requires its newer iDash on 2024-2026 trucks while older units are not compatible. Drop-in variable-geometry turbos carry different part numbers for 2024-2026 than for 2017-2023, and 2024-and-later pistons, heads, injectors, rails, valve springs and turbo actuator are revised, so anything cataloged for the earlier trucks needs verifying. Intakes split again at 2025 for the crankcase-ventilation sensor. The 5-inch DPF-back systems here are single-rear-wheel only, so a 3500HD dually needs different tailpipe routing. Ring gears differ between the 2500HD at 11.5 inches and the 3500HD at 12, which keeps ring-and-pinion sets and covers from crossing. Note the transmission RPO, MGM or MGU with the engine-driven PTO, when you order transmission parts. AT4X trucks already ride 1.5 inches higher on DSSV dampers with 35-inch tires, which is also the factory-validated lift and tire envelope on this platform, so leveling parts written for SLE or Denali need a second look. Spring and air-spring choices should use 2024 weights rather than older numbers, since 2024 diesels weigh up to 271 pounds less and 2500 models lose up to 332 pounds off their payload ratings. Tow ratings vary by cab, bed, two- or four-wheel drive, single or dual rear wheels and the Max Trailering package. And after any wheel change on a 2024-2025 2500 with enhanced towing and 20-inch accessory wheels, confirm the rear pressure and run a TPMS relearn: recall 26V-530 covers an incorrect tire pressure label.

Frequently asked questions

Is the 2024 Sierra HD diesel really a different engine than the 2023?

Yes. It is the same 6.6L L5P family, but 2024 is a revision, not just a recalibration. Output went to 470 hp and 975 lb-ft, GM points to the control architecture, combustion system and turbocharger, and aftermarket sources add revised pistons and injectors and the new E42 controller. The practical takeaway is that the 2024 turbo does not interchange with 2017-2023 drop-in units and replacement injectors have to be matched to this engine and coded to it.

There is oil seeping near the oil cooler on my Sierra 2500HD. Is that known?

It is. GM bulletin 25-NA-150 covers engine oil leaks at the oil cooler on 2024-2026 trucks and says damaged seals are the cause, so the seals get replaced if they are damaged or debris is found and the cooler only goes if the seals look fine. Watch for oil in the coolant reservoir, steam or a rising oil level, since owners have reported oil getting into the cooling system, and expect to ask about part availability.

I got a handful of glow plug codes on one cold morning. Do I need glow plugs?

Probably not. On 2024-2026 trucks GM says do not replace glow plugs before checking the Battery Distribution Unit and the engine harness connector. Verify 12 volts at the BDU ring terminal while wiggling the cable, inspect the X950D 55-way connector for bent terminals, and replace the BDU assembly if fuse contact is intermittent. Several glow plug circuit codes setting at the same time points at one shared connection, not eight separate failures.

My Sierra is an AT4X. Do standard HD suspension and wheel parts apply?

Not always. The AT4X leaves the factory 1.5 inches higher on Multimatic DSSV dampers with 35-inch tires, so lift and leveling kits written for Pro, SLE, SLT or Denali trucks have to be checked against that starting point. That factory setup is also the validated ceiling for lift and tire size on this platform, which is a useful reference if you are sizing wheels and tires yourself.

What should I watch when I tow heavy with the 10-speed?

Use Tow/Haul and the exhaust brake on grades, which protects the service brakes and helps the particulate filter regenerate. Keep an eye on DEF: heavy towing can set a low or empty warning shortly after you leave or make the tank refuse a fill, and GM's guidance is to wait for the speed-limit countdown message and then add at least two gallons. If you are getting derate or DEF complaints under load, weigh the combination and confirm you are inside the rating. And since towing temperature is what wears the 10L1000, keep the fluid and filter services on schedule.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.