green is 30k coolant and requires the additive....
gold is 100k coolant (i wouldnt run over 60k on it though myself) and requires no additive
If green and gold are mixed....ford says to then treat the vehicle as a green coolant vehicle. Ford claims you can go from gold to green with no problems, but you cant go from green to gold. You will never get all the green out so going to gold is almost impossible based on what ford claims....