Can anyone point me to an article on how this drive system really works? I've had my hubs apart and fully understand how they engage, but how/what makes it selectable?

As much detail as possible...I like to know what is going on with my toys.

Thanks!!!

 

I've looked at the system on my xplorer and couldnt quite grasp what was really going on in there when in 2wd vs. 4wd maybe someone can explain it to us.

 

Don't have an article but if you're talking a newer machine, the switch actuates a solenoid in the front central hilliard gear which engages the front drive. When a rear wheel slips the transmission transfers power to the front driveline giving you a locked front and rear diff or "true" 4WD.

 

I understand the mechanical part, but not how it can be selectable.

The front axles drive a hexagon 'gear' which spreads six rollers out toward a honed hub when real wheel speed exceeds front wheel speed. The hex will jam the rollers against the honed hub and produce drive to the front wheels. What I don't understand is how/what stops this from happening when you are in 2wd.

You'll have to forgive my terminology on the parts as I haven't seen any literature on these parts.

 

roller sprag !!!

 

When you are in AWD, a magnetic coil activates, allowing the above to happen. When in 2wd, the coil is not magnetized, preventing the hubs from engaging. I believe it is the armature plate that the coils act upon to engage or disengage the system.

Remember, when in AWD, you are merely PERMITTING the vehicle to engage all 4 wheels when needed. If you have traction only 2 wheels are being powered.