They make an impact socket with a screwdriver blade as thick as the slot in the end cap. Fits a 1/2" impact tool. If there is a garage around you that's been in business a long time they probably have one. Snap On and OTC still sell them but a bit pricey for one time use. I have two different sizes and have never had to heat the rod end in the last 58 years. It must make a mess when all the old grease catches fire and runs out--smelly too.
