Ever since I lifted I get a weird whine/roar from my driveline somewhere sounds like it is from the rear, but I only get it when I let off the gas over 55 mph or so, does not happen at lower speeds, does not happen when accelerating..... My dad seems to think it might be vibrations from the crazy tread pattern on the new tires, but I remember noticing it after the lift before the tires went on, I thought it was simply wind going underneath the VX different than normal, sorry no help, but I experience this kinda. Could this be from changing to full synthetic diff fluid? Do we need thicker fluids?