The old pilot bushing can be removed with a slide hammer-type tool, often available for loan or rent from local parts stores. But if one isn't available you can improvise with a drift, steel rod or, ideally, an old transmission input shaft. The trick is to fill the entire cavity behind the pilot bushing with grease, then hammer your steel rod through the pilot bushing and into the grease. The hydraulic pressure generated will push the pilot bushing out. You may have to stop and add grease several times in order to fill the void left by the exiting bushing, but you'll be amazed how well this trick works!