Ok this is probably a real dumb question, but I just bought my first 4wd Silverado. Its a 2004 Z71. Anyways I saw a service 4wd light come on once and made me start playing with the feature. It goes into 4wd and works but just doesnt seem to be smooth at all very rough and jerky especially while turning. Is this just how it is w/ 4wd or do I need to have it looked at? Any help is appreciated. Thanks.
The type of situation you are experiencing with your four wheel drive truck is a normal condition and does not need to be diagnosed any further.
When you shift into four wheel drive you activate the front wheels so all the wheels have torque applied to them. You feel the difference when you try to go faster or when you make turns.
Couple other things. If you saw the 'service 4WD" light come on there is a diagnostic trouble code in memory that needs to be diagnosed.
But it may not have anything to do with what you're feeling. Like TechHelp2 said, it most likely is a normal condition. If it's a "part time" 4wd transfer case you should NOT have 4wd engaged in good traction conditions. This can cause axle (drivetrain) damage while making turns. Only use 4wd in low traction conditions.