There is a link in my signature to a video as a reference to the sound of a 46, granted I have a 2 ton, its the same 4 speed transmission. There is plenty of gear whine in 1st through 3rd. 4th is pretty quiet. Any whine you can hear in the video with the 4 speed in 4th is the auxiliary transmission, it whines in both under-drive and overdrive. Next time I have a load and remember the camera, I'll capture what it sounds like working, no load in the video. The whine in 2nd and 3rd loaded to the weight rating and pulling a hill is like nothing else.
The whine however, does not induce vibration that can be felt anywhere in the truck. Sounds like that sloppy u-joint could be a contributing factor, but I'm not that familiar with the enclosed driveline trucks.
