The difference between 2wd and 4wd is amazing when things get slick. our lane is all up hill from the gravel road we live on and the gravel road is very hilly.
Without 4wd I always made it in and out but with very aggressive driving and good tires.Many times I would have to back all the way down the hill and back up the other side until I quite moving.Yes weight on the truck helps a lot.But weight does not help when you hit ice in fact it makes it worse.
4wd has allowed my wife to drive in and out of our road anytime she wants. In fact when others have gotten stuck at the bottom of 2 hills on our road she has driven them to the top in one of our 4wd truck or jeep and I have driven their vehicle out.
We avoid driving on snow or ice because of other drivers we may encounter. Especially on the interstates. Every time it snows somebody looses it and crosses over the center into the other lanes and when someone is spinning around coming down the road in your lanes there is not much you can do.
2015 F350 Lariat CC LB 4x4 DRW 6.7, 6sp auto, 3.73
2000 F350 lariat SC LB 4x4 DRW 7.3, 6sp manual 3.73
1987 F250 Lariat SC/LB 4x4 SRW 460 4sp stick 4.10
1995 Jeep wrangler
99 Star Craft 953