Snap-on offers its Injector Puller Kit (IPK1170) for GM LB7 Duramax engines, which is designed for removing the sleeve from the injector without causing damage. 

The Snap-on Injector Puller Kit is designed to remove the diesel injectors from GM vehicles produced from 2001 to 2004 with an LB7 Duramax engine. These engines are found in light-duty 2500/3500 and medium-duty 4500/5500 GM trucks.