Hi all, my 2007 Outie engages the rear wheels when I do a tight turn on loose gravel. Is this correct?

I had this before in a Mk2 CRV and it was the diff fluid. I have changed the diff and gearbox fluid but it still does it.

Is there an issue with my 4wd system or is this normal?

I have checked the data through an iCarsoft OBD reader and the voltages change when using the 2wd/4wd mode selector so that seems to work correctly.

I'm just checking if it is normal for these or mine has an issue.

thanks

Jim