960 4 speed auto - winter mode + Low gear

Alright

My parents took the 960 for a bit of an off road adventure this past week.
Way up North on some muddy and deeply rutted logging roads, filled with
water, wet clay sheer surfaces, and some normal mud.... the car looks REAL
pretty right now... to a 4X4 enthusiast anyways.

Anyhow, they didn't get stuck, but my dad said he used Winter mode, and Low
mode at the same time.... I thought Winter was 3rd gear only, and Low was
1st and 2nd gear, whichever one you are in at the time, or the highest gear
out of the two when the car is downshifting (like coming off the highway or
down a hill)

My dad said all winter does is locks up the limited slip, and that Low keeps
it in low gear.

What does the combination do exactly?.... All I know is that he didn't get
stuck in ruts where some pickup trucks were getting poped tires, and at
least one got stuck (a RWD light pickup... less traction then the Volvo)

Ground clearance was fine, but he had to drive on the crowns of the ruts
most of the time .... he said the car can drive thru nearly a foot of
water and remain fine....

 

Winter mode in "D" starts in 3rd gear, and will allow upshift to 4th.
Winter mode in "3" locks the transmission in 2nd. Winter mode in "L"
locks the transmission in first gear.

 

Alright, thanks...

Am I right in saying the limited slip differential will lock up as required?