Vib
Not sure if your still dealing with this vibration. However I had the same problem. Same speed and same shift to neutral and same coasting down hill. My vib was worse on deceleration than acceleration. I checked the same things you have checked and replaced much more. I did the CV's and tires and even purchased tires and wheels. In the end the problem was faulty troubleshooting. I didn't remove my drive shafts and when I checked them they felt solid. so I moved on. The u-joints were so bad on mine that they pinned and felt good and solid. I cant tell you what the problem is, but maybe recheck the easy stuff. Drive shaft.
Good luck and let us know so we learn too.
Thanks Russ
Not sure if your still dealing with this vibration. However I had the same problem. Same speed and same shift to neutral and same coasting down hill. My vib was worse on deceleration than acceleration. I checked the same things you have checked and replaced much more. I did the CV's and tires and even purchased tires and wheels. In the end the problem was faulty troubleshooting. I didn't remove my drive shafts and when I checked them they felt solid. so I moved on. The u-joints were so bad on mine that they pinned and felt good and solid. I cant tell you what the problem is, but maybe recheck the easy stuff. Drive shaft.
Good luck and let us know so we learn too.
Thanks Russ