Thanks for the quick reply Kalsc,

I just crawled out from under the truck. There's definitely play in the rear joint. Front and middle are tight. Looks like I have an afternoon project. ;-)

Yes, I have 3.5" Fabtech spring-hanger lift on the front, 4" blocks in back. I noticed the drive-away shudder the moment it was installed. Same as you described...only noticeable under heavy acceleration. (3) 1/4" flat steel shims eliminated the problem on my truck, but the amount of shimming varies depending on lift height and axle-to-axle length.

Matt