Chey Duramax Front Diffy - How it works

[stockrex]

My LMM duramax is a on the fly shift knob 4wd

Can someone explain to me how the front diffy works.
I see an electric motor that actuates, but what about inside?

I just changed the oil with new syn oil. Front diffy definitely makes some noise and vibration, but under load it sounds it will come apart. Surely this can't be good. It sounds like loud whirrling. Don't know how to describe it,

 

[JMJNet]

Have you checked YouTube?

 

[demarpaint]

Originally Posted by stockrex

My LMM duramax is a on the fly shift knob 4wd

Can someone explain to me how the front diffy works.
I see an electric motor that actuates, but what about inside?

I just changed the oil with new syn oil. Front diffy definitely makes some noise and vibration, but under load it sounds it will come apart. Surely this can't be good. It sounds like loud whirrling. Don't know how to describe it,

Did it have those symptoms before changing the gear oil? Or was the gear oil change done in hope to resolve those issues?

 

[clinebarger]

The actuator controls the Central Axle Disconnect....Which is just a splined collar that connects/disconnects the right outer axle shaft from the inner axle.

When disconnected......The only moving parts are.
*Right outer axle shaft.
*Right inner axle shaft (Rotates opposite direction)
*Left axle shaft.
*The Spider gears & Side Gears
*The Caged Needle axle support bearings.

The Ring Gear, Carrier, & Pinion Gear/Yoke remain stationary (Assuming the T-case is in 2WH).

When 4wd is commanded....The CAD Actuator connects the right Inner & Outer axles together.....The front diff is now just like any other open differential.

The CAD Actuators have a long history of issues, But you usually get flashing 4wd button indicators or a Service 4wd Message in the DIC as the Actuator has a position switch built into it.

Jack up & support the front of the truck, Front wheels off the ground. Check both front wheel hub bearings first!!
You should be able to rotate both front wheels with little resistance, And one wheel souldn't rotate the other!
The front drive shaft should spin freely & not rotate either front wheel.

 

[stockrex]

Checked youtube but nothing close to my issue.

Issue was there before oil change, the main vibration/noise is still there, new oil made it a little quieter.

in 2wd
I do not have means to lift it up,
Front drive shaft has a little binding at a certain spot when I spin it.

4 wd high the front diffy howels pretty house under load.

2wd
in 2wd the I get a front diffy area howel and vibration under load.

Only thing I read was that the actuator sometimes does not de-engage fully. I am heading out to the beach this weekend