Select Trac is quite different from Command trac

I checked jeep website and found this link
http://www.jeep.com/en/4x4/how_systems_work

Here is the definition of Select-Trac
-----------------------------------------------
Selec-Trac II supports the new MP 3022 two-speed, full-time active "on-demand" four-wheel drive transfer case. When driving in 4WD Auto mode, the transfer case clutch pack predicts conditions that may cause wheel slip and instantly applies increased or decreased torque between the front and rear axles based on real-time driving conditions, thus optimizing traction. Under the right conditions, the vehicle can be driven by just one wheel. For added capability when traversing steep grades, rough terrain, or extremely poor tractions surfaces, the transfer case includes a 4WD Low mode. Electronic shifting between 4WD Auto and 4WD is accomplished via a console-mounted switch. A 2WD mode is also provided.
---------------------------------------------

So it does provide a 4WD Auto mode for dry road.
The thing I am not sure is how did it allow front and read wheel turn at different speed? This definition says

---------------------------------------------------
the transfer case clutch pack predicts conditions that may cause wheel slip and instantly applies increased or decreased torque between the front and rear axles
-----------------------------------------------------
Seems it is not the center differential, but the transfer case some how allowed the front and rear axle
rotate at different speed.
Does it mean even select-trac does not have center differential?



But I believe this statement you have is correct
-----------------------------------------------------
wrangler没有一个档位叫做4auto，可以像4runner一样平时也可以挂上四驱
------------------------------------------------------
Jeep.com listed that wrangler is only equipped with either Rock-Trac, Command-Trac. So you are right that
wrangler does not have 4wd auto mode.

But did anybody add a center differential to
Wrangler (I know you don't like it, just asking)
so that it can engage into 4wd on dry road?

所有跟帖： 

• 没有人会考虑在wrangler上加上一个中央差速器的。 -杀雨- ♂ (1041 bytes) () 07/02/2009 postreply 21:30:50

• Agree, I just asked the question in theoritical sense. -wolfmanii- ♂ (2189 bytes) () 07/02/2009 postreply 22:14:53