Last year, I got new tires: Yokohama Geolander G015 for our 2000 LandCruiser. The rear passenger side tire has a nail in the inner sidewall & can't be repaired (per Discount Tire) & it has a slow leak (down to 10 PSI about weekly). We have put 16,000 miles (highway pavement) on the truck in the 1 year plus 4 months we have had the tires. Can I replace just the one leaking tire? Do I very sadly need to replace all of the tires? They have been great tires year round in Colorado.