Does a 1999 Chevy Prizm have 15 bolt or 18 Transmission filter?

The 1999 Chevy Prizm uses a 10-bolt transmission filter, not 15 or 18. There's no standard "transmission filter" in the way some older cars had an easily accessible external filter. The filter is integrated within the transmission itself and requires a complete transmission fluid and filter change. There is no readily accessible bolt-on filter.