If the gear puller alone wouldn't pull the gear off alone then I would reccommend using a propane torch and heat the gear up to expand the sleeve and then use the gear puller to extract it. This is the gear that drives the timing belt correct and not the harmonic balancer? Either one I would plan on replacing the crank seal and if it's the harmonic balancer plan on replacing that as well. The hear will ruin the harm. bal or crank seal and they should be done anyway to prevent oil leaks or timing marks to be out of line and accessory belts from slipping.