Can I ask a very basic question about our 4wd system?

I recently greased my u-joints. I lift the back wheels up securely so I can spin the wheels in order to turn the rear driveshaft to target the zerks. Easy.
The front. In 2wd, I simply reach up and spin the driveshaft. Front wheels are on the ground.

When we engage 4x4, the axes at the center diff lock up, right? (Versus at the hubs) Then it locks up at the transfer case as well? Or is the driveshaft (front) always locked at the transfer case, and when I was spinning the front shaft, I am also turning the internals of the t-case?


Cabin fever might be setting in.

 

your front end never really spins freely unless you have manual hubs, your just not sending power to the front while in 2wd. the tcase just splits the power to the front and rear when you engage 4wd.

someone else can go into this more im going home.

 

That what I thought but you can spin driveshaft with front wheels on the ground.

 

In 2wd the front disconnects the pass. axle and the t-case, when you turn the dvshft you are turning the ring & pinion inside the diff and the spider gears for the drv side rotate around the shaft.

 

Thank you so much.

 

That’s called the ADD system if you want to read more on it. I forget what it stands for.