2005 3500 driveshaft support bearing

[greasemonkey]

Hi guys,
I'm working on a 2005 3500 4x4 DRW. I've got a vibration starting at 65 mph, the tires have checked out ok, and I've moved to the driveshaft. Someone has changed the center support bearing recently (I just bought the truck this year) with a cheap Anchor parts store special. It's not installed very well, as the sleeve that the bellows attaches to is loose and flopping around. The support is the kind that has the spacer under it, bringing the centerline to 2.6 vs the 2.2 other supports have. I've found a lot of info about which part numbers are correct, and I've gone through the Spicer catalog to find the differences. The one difference I find is that some have a spacer and others don't. The truck sits pretty high from the factory, but I'm not sure whether it is supposed to have that spacer on it or not.
Thanks for any input! John