I've got an '89 4-Runner. I'm in BC, Canada. We don't get much snow here, and I don't go 4 wheeling very often. We just got snow, but it's the kind that isn't sticking to the roads, but piles up on the side streets. I went out using 4wd, and it was great on the side streets, but on the main roads, where it's just sort of wet pavement, I get a loud grinding with a bit of vibration from the front left wheel. I think this is due to too much friction for 4wd, but I want to make sure I haven't done any damage. I'm taking a road trip in Dec that will require driving through the mountains. How snowy/icy does it have to be in order to warrant using 4wd. I don't want to slide off the road with 2wd, but I sure don't want to wreck the truck. Any advice would be much appreciated.