Know your uncertainty! I did my original owner 1997 J30T 108,00 mile timing belt change at 40,000 miles and now have the option/necessity to do the 216,000 timing belt change at 56,000 miles. YES! I have a very low mileage original vehicle. Long story but bought for retirement free travel and cruising but fate said "NO" . [Long story, you do not want or deserve the details.] Wrong reason, right car ! Since it is 21 years old I think I will cave in and go for another timing belt change and insist on the "standard" belt, tensioner and water pump kit supposedly available from dealer stock.