Hey Guys, can anyone tell me if this is normal:

Got a 2010 silverado 5.3/ 6 speed 3.08 rearend.

When accelerating from 20-40, heavier foot, you can feel almost a shudder through the cab, nothing bad, but noticable.

Is this normal? Vibration and lugging felt through the cab created by the engine?

Or is this something worse, like drive shaft u-joint going to heck? If so, how can I tell the difference? Maybe someone can drive thier truck and see the same?

Thanks in advance