2016 Silverado with 52K on it. Noise when turning over speed humps. Been at dealership 2 times for bulitins saying problems with leaf springs.. Today they said they put a heavy duty grease between the springs. Noise is gone now. But question is how fast will this noise return. I have seen others with problem the same but this is first 2016 ive heard of with this problem. Biggest problem is my warrenty is out at 60K and I was told they will not help any longer. Where and what is the real problem?