I have a 1984 Land Cruiser FJ60 with 196,000 miles. It runs great, uses about 1 quart of oil every 2500 miles. I change oil every 2500 miles, which for me is 4 times per year. During most of the year I run Delo 15w40, but during the 3 hot months of the summer I switch to Chevron 20w-50 (hey-it's $0.69 per quart!). I was at Wal-Mart today and bought 2 gallons of the Shell Rotella T synthetic 5w-40. I'm thinking of running this over the winter this year-my next oil change will likely be in November. Does anyone see any issues with this? I don't have any oil leaks, at least not motor oil anyway. If I run this stuff November-March, it will likely accumulate 4000 miles or so which is a bit longer than my usual interval. The climate here is mild, the low temp might hit 30 degrees. I will go to Tahoe several times, and will be spending a week in Death Valley in Febuary, so there will be a few cold starts at maybe 20 degrees. I've been a Chevron guy on my older Land Cruisers forever so the Shell is out of my comfort zone. Should I just stick with my usual Delo 15w40 (my normal winter oil), or is this synthetic Rotella the real deal? My oil capacity is 8.2 quarts if that matters. Thanks for any and all replies.