Where is crankshaft position sensor on 2001 Chevy 2500hd 8.1 liter motor?

The crankshaft position sensor (CKP sensor) on a 2001 Chevy 2500HD with the 8.1L engine is located on the passenger side (right side) of the engine block, near the front of the engine. It's usually mounted relatively low and points towards the crankshaft pulley. You'll likely need to look underneath the vehicle for the best view of it.

Important Note: Accessing this sensor might require removing some components for better visibility. Consult a repair manual specific to your year and engine for exact location and removal instructions. A repair manual will also show you precisely where the sensor is located to avoid mistaking it for another component. Pictures within the manual will be invaluable.