In my experience, that’s rare. Most AWD systems that I’ve seen use an open differential with no viscous coupler or locker of any kind. The '94 - '97 Toyota Land Cruiser (w/ ABS) in the US market used a viscous coupler, and Toyota called it “full-time 4wd”. It also locked the transfer case in low range. To my knowledge, this was a really unusual configuration. They discontinued the viscous coupler after that, instead switching to their ATRAC traction management that used individual application of brakes to prevent wheel spin. Most of the Jeep SUVs in the last ~30 years, to my knowledge, used an entirely open center differential in AWD models.
It seems like modern, CUV AWD systems are usually FWD with computer controlled engagement of rear tires.
In my experience, that’s rare. Most AWD systems that I’ve seen use an open differential with no viscous coupler or locker of any kind. The '94 - '97 Toyota Land Cruiser (w/ ABS) in the US market used a viscous coupler, and Toyota called it “full-time 4wd”. It also locked the transfer case in low range. To my knowledge, this was a really unusual configuration. They discontinued the viscous coupler after that, instead switching to their ATRAC traction management that used individual application of brakes to prevent wheel spin. Most of the Jeep SUVs in the last ~30 years, to my knowledge, used an entirely open center differential in AWD models.
It seems like modern, CUV AWD systems are usually FWD with computer controlled engagement of rear tires.