I've got a 98 k1500 z71 and I have noticed recently that the back end of the truck sags quite a bit and is noticeably lower than the front. I know its a z71, but it rides really rough and shakes the piss out of ya whenever you go over something like railroad tracks. Also, whenever I pull up on even really slight grades and park, one of the rear tires get stuffed really bad, this is just a slight slope, nothing steep. And even just sitting on the tailgate will lower the truck significantly. I imagine its the shocks, but want to make sure if its not the leaf springs?