Coolant drain and fill is recommended at 90,000 miles; spark plugs at 105,000 miles. I usually drain and fill the automatic transmission fluid every 30,000 miles, using Valvoline Maxlife ATF. I service the transfer case and diffs at 60,000 miles. Make yourself aware of the radiator cooler leak issues that affect these vehicles. If you have a Calsonic label on the top tank of the radiator with a part number of 21460-EA200, 21460-EA215 or 21460-EA265, then you should replace the radiator or bypass the radiator cooler if it hasn't been done already. If you lift your truck and don't get bigger tires, you probably won't be happy with the way it looks.