I recently added new Deaver leaf springs to give me 1.5" of lift and now I have a grinding that feels like I'm driving over rumble strips at 22-32 MPH. It does this in neutral and drive. It gets worse when I accelerate in this MPH range. It has been doing this for over a month now and is progressively getting worse. At one point, my truck bed was loaded with at least a couple hundred pounds of gear and I drove it over 150 miles and I never experienced the grinding. I've shot more grease into the driveshaft and that will quiet it for a little bit. I've noticed that the grease from the driveshaft has been thrown around where the two pieces meet. This is new with the install of the rear lift. I suspect that the grinding is coming from the driveline since it now is being stressed from the rear lift. Thoughts?