Lookin at this 99 sub with 121k miles. 2 things i noticed.... on the highway it rides a little rough when you drive over the tar seams in the road. assume it's the shocks. then we go over a patch job on the highway and OMG!!! What is that rattle?? it's just the road he says, didn't you notice how smooth it was on that other road. well, yeah but it was a smooth road, don't need any suspension on that one. it felt like someone just shook the truck when i go over these patch jobs. I was thinking of offering him 300 bucks less to split the difference in a shock replacement, but what if i buy this and this doesn't fix the problem??? then at 40mph to 50mph i believe there is a howl comming from the front end. not at 35pm and not above 55mph. looking back at his records i saw that there was a note about the front diff needing servicing long time ago. makes me a little nervous. The repairs on this truck are unbelievable! New fuel pump, u-joints, ball joints, steering sensors, and the list goes on.... dad has a 3/4 ton durmax with 111k miles. nothing replaced except for 1 brake job, tires, and injectors. runs smooth and no crazy shakes on these same patch jobs. what do you think about the shakes and noise? lemon sub???? or has he just done the required maintenance for this truck and it's in great shape except for needing new shocks? he did get new shocks at 70K miles, maybe he just got some cheaper onese that didn't last too long.