shift knob moves to the left in drive ?

Just purchased a '13 Tacoma 4x4 sport....for winter driving. The shift knob can be moved to the left of the D position. What is that about and does it have anything to do with 4x4??? nothing in the manual about this. Owned a Forerunner in 1988 so I know about 4x4. Anybody have this "problem" ?

 

You're just switching it to 4th gear. It prevents from overdrive to engage. The 4x4 switch is next to the steering wheel under a ac vent.

 

Going to the laft from "D" is just taking it out of overdrive and into 4th.
Nothing to do with 4x4

 

The only problem I have is when my wife drives. She doesn't seem to understand that it needs to be in "D" most of the time. For some reason she has a mental block when she drives my truck and thinks it is supposed to be driven in 4th gear.

It isn't a real problem around town. But I've let her drive for a few hours on some long road trips while I rested. I figured it out when I noticed that when she drove fuel mileage was always 2-3 mpg worse than when I drove.