[777stickman]

Originally Posted by johnnyrocker

clicking from drive line on 99 gmc suburban ? speeds up with acceleration at freeway speed (70) it sounds like a plastic bag rattling under the truck. what would make such a sound universal joint? transfer case? please help.

Welcome to the forum: It could be anything, even a plastic bag. Need to get under it with all 4 wheels off the ground preferrably on a good lift. With it off the ground, in 4HI, in gear and motor running you should be able to pinpoint were the niose is coming from quickly. Just stay clear of all the moving parts!!!