“Quadra-drive” is Jeep’s branding for full-time 4wd. It’s one of the several options you can choose on the Grand Cherokee. The other options are various flavors of Quadra-Trac, which is also an always-on 4x4 system.
And I’m not too sure on this one, but the Activedrive system, available on the less-than-grand Cherokee, is listed as automatic, but the sales literature doesn’t say if you can disable its ability to enter 4x4 mode. If you can’t, then it should be treated as full-time because you never know when the car will decide it needs to be in 4x4 mode.