Genuine GM Crankshaft Assembly 12708884 – Suits Gen V 6.6L L8T V8 (Silverado/Sierra HD)
Genuine GM Crankshaft Assembly 12708884 – Suits Gen V 6.6L L8T V8 (Silverado/Sierra HD)
Genuine GM Crankshaft Assembly 12708884 (supersedes part number 12701676) is a factory-forged steel crankshaft designed for the GM Gen V 6.6 L L8T V8 engine. This crankshaft features a 3.860″ stroke, integrated 58-tooth reluctor wheel, and 8-bolt flywheel flange—making it the direct replacement for high-demand Silverado/Sierra HD applications.
Manufactured from high-strength forged 1053/4340 steel and precision-balanced to OEM standards, the 12708884 crankshaft delivers exceptional durability for heavy-duty, towing or performance use. Each unit includes the pre-installed reluctor ring for seamless integration with GM engine management systems.
Fitment:
- Chevrolet Silverado / GMC Sierra HD (6.6 L L8T V8 – Gen V)
- GM performance builds using the Gen V 6.6 L L8T engine
Specifications:
- OEM Part Number: 12708884 (replaces 12701676)
- Engine: GM Gen V 6.6 L L8T V8
- Stroke: 3.860 in (98.0 mm)
- Reluctor: 58-tooth – Installed
- Flywheel Mount: 8-bolt pattern
- Material: Forged 1053 / 4340 steel
- Balance: Internal – neutral counterweight design
Key Features:
- Genuine GM OEM crankshaft – factory specification for L8T applications
- Forged steel construction for maximum strength and reliability under heavy loads
- Pre-installed 58-tooth reluctor ensures accurate crank position signal
- Precision-balanced and heat-treated for smooth, long-life operation
- Ideal for factory rebuilds or performance/towing builds using the Gen V 6.6 L engine
Installation Tip: Fully clean oil galleries and journals before installation. Use new main and rod bearings, torque bolts to factory specs, and balance the rotating assembly if mixing aftermarket components.