[iadr]

So I drive a Sidekick. When it's really slippery (snow), I drive in 4H.
When I brake aggressively, it definitely resists wheel lock up better in 4H than in 2wd. (No ABS)

I *almost* get what must be happening, but I need someone else's words to clarify I have it. Or "have" the last 5%.

The outputs to front and rear axles have to be the same at the transfer case.

The diffs are open ones.

So when one wheel locks, the other has to either spin 2x as fast- which isn't going to happen, or.... or what? An engineer would say, the total RPM of any axle pair of wheels has to equal the other axle pair.
But I'm still not intuitively getting it. Talk me through it- the backwards torque, etc?

 

[GreyZuk]

What year sidekick do you have? I would think braking is braking is braking.
Unless you are:
A. using gearing to assist in braking. or
B. have a much newer vehicle that senses slippery conditions and alters the modulation of the ABS system... ?????

 

[Chrisbuilt]

Normally the rear axle will lock up easier due to weight transfer under dry conditions. However, this doesn't normally happen on ice or snow. The weight transfer is reduced because of the limited traction which means that the rear tires will have more weight on them. This keeps them rotating and the mechanical lock between the axles will force the front axle to rotate as well.

I hope my basic rational helps explain it.