i have an 08 silverado 4x4 with the 4.8. i want to know why it wont spin tires or even takeoff fast and how to fix it.  

throw a superchager in it, the 4.8 just dosnt have enough power...nor does the 5.3 my 5.3 wont spin unless its wet out and even then i have to punch it. really the problem is that you dont have enough power.  

My 2500HD with the 6.0 won't spin them either, but it is because the gears are to high in the rear end, with the tow package on it. My buddies have 1500's in the 01-04 range with the 5.3 and they spin. Does your new truck has traction control? I know the 2008 Tahoes do because mom's Tahoe won't spin either.  

Throw it up in neutral, hold the gas wide open, drop the shifter in low. Hold on!!!!!  

Wouldn't that be VERY hard on the tranny????  

And the Drive shaft and Rearend.... It was a joke. Sorta like asking why my Truck won't spin.  

Yep. Not only that, the newer Vortec engines don't have a lot of low-end torque in my experience. If you put a super-short rear-end and a blower on it, I guarantee you you'll be able to do a mean burnout, but most newer  stock trucks can't do a burnout stock without doing some major abuse to the drivetrain.