Wheel Spin in snow - unknown noise?

[swalt]

Hey guys.  I have a 2006 Z71.  Whenever I am in 2WD and I get some wheel spin in the snow, I get this this sound from the drivers side that sounds like a pressure buildup/release crunching noise (like the brake booster is overpressurizing).  It only happens when I get the rear wheels slipping of the line or a bit of fishtailing in the snow...and its very noisy.  Is this something normal with these trucks and the brake booster or should I be taking it in for service? 

 

[Wayne]

If it is coming from the back of the truck I would say it was the rear locker activating. Do both wheels(instead of one) start spinning right after the noise?

 

[m02redl]

it might be the ABS system

 

[MS03 2500]

I think it's the ABS also what you hear as the power steering pump which is used to power the hydraulic brakes and it is cycling the brake on the wheel that's spinning

 

[swalt]

The pressure type noise is definitely from the front, like a pump.  So is this normal?

 

[MS03 2500]

Yep, and now you the ABS works