like kingkevindavis said, the flush gets the fluid out of the converter.. also the cooler and the lines, just dropping the pan won't do this. the flush machine uses the trans. pump to pump the old fluid out and push the new in, that's how they claim 100% fluid transfer. ford filters do a pretty good job at filtering the fluid and unless you have had major issues with the trans., you should be good i flush mine every 30k and change the filter every 60k so to answer your ?, yes the trans flush is well worth the money and will help keep your trans running good and i highly recommend it. imho, ford is trying to push the service intervals too far. in the guide for my 08 6.4..10k on the oil change for normal and 60k for trans and filter. no thanks, i will stick to 5k and 30k.. but thats just me.