We have an '09 Highlander with Full Time 4WD. Overall, it does a good job in winter driving but in deeper snow it tends to want to slide around a little on the road. Would the locking center differential on the full time 4wd in the 4Runner Limited improve performance in deeper snow? I've never found any AWD or Full Time 4WD to perform as well as a traditional part time system but I'm wondering if the locking center differential would make the difference. Thanks.....