Hi guys, I need some help , hopefully you can point me in the right direction. A while back I bought a seal kit from North West Fab for my NP205. While I had the 205 apart I installed a 32 spline front output shaft along with all the new seals/gaskets in the kit. Everything seemed to have gone together properly. I also installed a rear driveshaft from High Angle Driveline w/ a double carden joint on the 205 end and single 1350 joint on the rear end along with one of their drive flanges on the rear output shaft. This was coupled to the stock 12 bolt w/ 3.08 gears. So far so good. I drove it like that for a short while with no noticeable issues. I then replaced the 12 bolt with a 14 bolt rear w/ 4.10 gears (freshly built by Boyce Equip). On the very first drive with the new rear, I heard a loud growling type vibration at freeway speeds when I let off the gas. Thinking it was the new rear not being set up properly, I contacted Boyce who very graciously shipped the rear back to their shop, rebuilt it again (they said the pinion gear was slightly out of spec), and shipped it back to me. I reinstalled the rear, took it for a spin and experienced the very same loud growling vibration! During my inspection I noticed that the rear output flange on the 205 seemed to be loose. I dropped the driveshaft and sure enough the flange nut had backed off! I removed the nut, cleaned the threads, applied some blue loc-tight and reinstalled the shaft thinking I was good to go. Wrong. On the first test drive the noisy vibration was still there. Is it possible the transfer case needed to be rebuilt and the 4.10 gears are amplifying something that has always been there? Should the rear output flange have any wiggle to it when its torqued to spec (150 ft/lbs)? What should I look for to determine if the 205 needs to be rebuilt? According to the paperwork that came with the truck, it only had about 70k original miles on it. Any help is greatly appreciated!