The Alliant Power AP0203 is a new turbocharger installation kit for 2017–2023 GM L5P/L5D Duramax applications. Alliant’s Turbocharger Mounting Kit supports turbocharger service by providing components used during mounting or installation.

Features & Benefits

• New Alliant Power Turbocharger Installation Kit (Alliant P/N AP0203)
• OE or OE Grade gaskets and seals
• All materials and layers meet or exceed OE specs
• One convenient kit with all of the necessary components to get the job done
• Direct replacement for 12642410 / 12642429 / 12642432
• Backed by Alliant Power’s 24-month, unlimited-mileage warranty

Included in the Box

• 1x Turbo Air Inlet Adapter Seal OE# 12651147
• 3x Oil Supply / Drain Gaskets OE# 12691866
• 1x Positive Crank Case (PCV) vent tube gasket OE# 12671847
• 2x Turbo Oil / Coolant Banjo Washers OE# 12662187
• 1x Oil Drain Tube Return Gasket Bottom OE# 12642432
• 2x Oil Feed Line Gasket OE# 12642429
• 1x Turbo to Pedestal Mount Gasket OE# 12677294
• 2x Up Pipe to Manifold Gaskets OE# 12688018
• 2x Up Pipe to Pedestal Mount Gasket OE# 12676608
• 1x Catalytic Converter Gasket OE# 12672821
• 1x Catalytic Converter Clamp OE# 12683878
• 2x Intake Manifold Gaskets OE# 12642410

Application

• Chevrolet Silverado 2500 HD / Silverado 3500 HD (2017–2021)
• Chevrolet Silverado 2500 HD / Silverado 3500 HD (2017–2023)
• GMC Sierra 2500 HD / Sierra 3500 HD (2017–2023)
• Chevrolet Silverado 4500 HD / Silverado 5500 HD / Silverado 6500 HD (2019–2020)
• Chevrolet Silverado 4500 HD / Silverado 5500 HD / Silverado 6500 HD (2019–2023)
• Chevrolet Express 2500 (2021)
• Alliant Power lists additional vehicle applications for this part number

Always verify fitment against your VIN, engine, and OE part number before ordering.

Cross-Reference / Replaces

• General Motors: 12642410, 12642429, 12642432, 12651147, 12662187, 12671847, 12672821, 12676608, 12677294, 12683878
• BorgWarner: 12709701044
• Alliant Power: AP0203

Warranty: Alliant Power’s standard warranty: 24 months with unlimited miles/hours on installed parts (Alliant Power warranty policy, rev. Aug 2025).