How does 2000's auto locking hubs work? And Trail repair question

[NYState4Runner]

Hey All,

I have a 2000 limited and I was curious if someone could explain the following:

1.) how does the auto locking hubs work and how are they engaged? (by what mechanism, I know you push the button to turn it on.)

2.) In the 2000 limited are the front CVs always spinning no matter if you are in RWD? To go from 2wd to 4H I just click the button, locking the hubs i am assuming, and never move my transfer stick. Only have to physically shift if I wanna be in 4HL; does this mean 4H is technically always on and the hubs just connect, or does the entire front drivetrain come to life when I click the 2H/4H switch.

3.) if you broke a front cv, can I just turn off the hubs and drive home in RWD?

 

[NYState4Runner]

I have the e-locker, with the 2H/4H button and 4HL + 4LL on the stick. So it does have the center locker and I also was unsure how that affects what components are spinning / engaged when in RWD, then vs when hitting the 4H button.

 

[phattyduck]

The front does not disconnect at the hubs. The ADD system disconnects the right side drive output of the front diff. When the front is 'disconnected' the 'right' output off the diff drives nothing, which means the prop shaft freewheels (doesn't spin or only spins slowly, depending). The front CV axles spin with the front wheels at all times, and a broken CV will have to be fixed in some way to drive at speed.

On the 99/00 Limited Multi-mode transfer case, moving the shifter from 2H to 4H does nothing mechanically. It engages a switch in the transfer case, which tells the 4WD computer to control the transfer case actuator to the "4hL" position. The only mechanical shifting in your case is from 4H to 4L. All the rest is done with the electric actuator on the back of the transfer case.

-Charlie

 

[Bad Luck]

To add to what phattyduck said above, when you engage 4hi the front differential ADD engages and connects and you get some power transmitted to the front axle from the transfer case, but the front and rear driveshafts are not locked together so the transfer case does not bind. When you put it in 4hi locked the transfer case "locks" the front and rear driveshaft together so it will bind (and potentially cause damage) if you are driving on a high traction surface like pavement.