That switch also disables the abs...
Anyways, yes it's normal. Its the tcs. Even when off, it's still on. All it does is tolerate more slip and stop killing the engine's power. When you were in 4low spinning tires going up hill it was kicking in. When going down, you said you used hill descent control. That uses tcs to slow the jeep as well, so yes all the noises were normal. Might seem weird and you're gonna hate hearing them, but they are normal. Not gonna lie, it's part of the reason as to why I don't use hill descent.
2011 KK - Skyslider - JBA Adjust-A-Strut - OME 731 - Bilstein Shocks - JBA UCA- 245/75-16 Duratracs