This noise started about a year ago, usually only noticeable on large dips at highway speed. Over time it has grown louder and more prominent with increasing occurrence. Now I get the noise over surface streets at 30-40MPH when there are big cracks or dips. It is easily reproducible on speed bumps, which I've provided some footage below. I can also feel the clunk below me/from the rear. Initially, I feared the worst -- possibly pinion bearing. I was finally able to use my daughter's GoPro and a magnetic mount and it seems to be from the slip yoke. There is no movement in the rear where the driveshaft meets nor any movement in u-joints. I will be changing the u-joints anyway. Should I invest in that nickel plated slip yoke? Hopefully packing some grease in there while the DS is out will help for now. What grease is recommended? I've seen some folks use some red from Lucas and others use the GM stuff. Watch the video and let me know what you think. Thanks.