It happens when I'm at speed. It starts at about 35 MPH and gets louder from there. And it only happens when im coasting. If I slam it down a gear going down hill it will go away cause its under a load. And I've got a brand new slip yoke on it with about 1/4 to 1/3 of it sticking out of the t-case. Its a 208 and I just took a grinder to the ears on the driveshaft and yoke to make sure it wasn't those ticking together. What the heck is causing this?