leaf springs

I just installed the Ironman HD leaf springs, both sides new shackles, bushings, u-bolts. it’s lifted my rear end up a lot. now, it has a vibration to it, and it sounds like a tractor going down the road at 25-35 mph. What could this be? never had any of these issues prior

For sale are the following OME suspension parts. OME SB100 Old Man Emu Spring Bushing Kit -2 Price: $40 for Pair OME60017 OME Nitro Sport Shock -2 Price: $220 for Pair OME CS016R Old Man Emu Leave Spring -2 Price: $420 for Pair OME U72 Old Man EMU U-Bolt & Nuts -4 Price: $ 40.00 for Pair...