On unibody MacBook, touchpad stopped clicking. Since I am using Tap to Click, that was not too big of a problem, but it was annoying. Touchpad was definitely "sitting" too low, because you could easily feel it "looseness" especially if you inverted MacBook upside down, and tap on the Touchpad. You would clearly feel and hear how much play Touchpad had.
Search on the internet revealed:
and together with iFixit MacBook Battery Replacement guide:
it was easy to remove the battery and correct Touchpad with the central screw.
Everything was easy by following iFixit MacBook Battery Replacement guide: MacBook Unibody Model A1342 Battery Replacement
Remove bottom, detach battery connector, unscrew 3 tri-wing screws (one hidden), unscrew 3 philips screws at the bottom, remove battery, then use Touchpad central screw to adjust Touchpad play. Be careful when doing this - the screw is very easily rotating. And be especially careful NOT to unscrew it completely. To "raise" Touchpad to its regular position where it can be clickable again, I have to tighten the screw.
Just follow iFixit manual, and just pay attention when adjusting Touchpad central screw not to unscrew it completely.