I've got an 04 Chevy 2500hd lb7. I get the range shift inhibitor sometimes and I've read guys will suggest the nsbu or the harness on the pass side of the transmission or last the ignition switch. Well my truck drives and shifts fine but the ignition switch didn't fix my symptoms. I'll drive 30 to 45 mph and my truck will randomly act like it's in neutral and give off a loud air pressure release sound as long as I press the pedal and once I let off and let it calm down itll drive again. But itll b seconds or miles down the road and itll do these symptoms again and again as long as I drive it. This is so aggravating to me not mention embarrassing and potentially causing more harm. Anyone ever have this problem or ever heard of this?? Please help I don't know diesels much but love and need my truck. Thanks a million in advance.