I have a 2008 crew cab 2wd silverado and it is doing the exact same thing,1ST AND 2ND WHINE, then normal just started about 2 weeks ago. I'm definetely out of warranty, about 86,000. Did Gm say I'm going to self destruct, it's a little spooky I don't want to be beside the road. I'm not sure what to do about it.