Haven't figure out exactly where my clunking sound is coming from yet. Definitely around the springs though. I guess some people with the BDS lift have had noise issues with the spacer not locking in quite tight, which means they left too much of the mounting bolt heads sticking out (In case you didn't know, the BDS spacers twist and lock in place via 3 bolt heads in the factory Air Spring mounting slots). I've heard that can be fixed by applying RTV sealant to the spacer and then installing.
As for the Z71 springs themselves, if you look at the parts for the Tahoe, they have the rubber isolators on top and bottom of the spring. For whatever reason, they only go on the top of Trailvoys..

. For a $8/each part, next time I have the springs out for my AirLift install, I think I'll put an isolator on each end, including RTV sealant on my BDS spacer. I'll need to pull the springs out to do the install anyway so I can run the air lines through the top isolator. Damn things don't come with holes..

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