My whirlpool duet front load washer has loose fins in the tub. how do i tighten them??

You're not gonna like this:

Pull the washer tub (see elsewhere on FixYa for step-by-steps), split the tub by removing the screws holding the two halves together, and remove the inner tub. Bend any tabs tighter that hold the fins on, and tighten any screws. While you have it apart, check for grease stains or other leakage on either side of the outer tub, and ensure the inner tub bearing is tight so that the inner tub shaft rotates smoothly and without oscillation. If there are stains or if the bearing is showing wear, replace that (back) half of the outer tub to replace the bearing (unless this is one of the few machines that allow you to replace only the bearing). You don't want to put all this back together, only to have to take it all apart again when the inner tub starts hammering on the inner tub because the bearing went south.