2004 freestar van jus stopped pulling while going down road about 45 mph now it wont even go in gear, is this a simple cable problem or more serious?

pulled the pan and the fluid is dirty but no metal already, paid for a filter kit and more fluid already can the transmission relay be replaced by me or is that over my head thanks

If it will not go into any gear including reverse it is possible that the linkage is came off the transmission. Usually when a transmission goes out, it only goes out in one gear. So it could be a linkage problem. When you open the hood the linkage will be on the drivers side. You can have someone get in the vehicle and operate the shifter to locate the linkage. If the linkage is moving properly, it still could be a minor problem. Is the check engine light on? If so, it could be the Automatic Transmission Relay.

You can change it yourself. It just unplugs and the new one plugs right back in. They are sometimes difficult to get to. But if you go to a transmission shop to get the relay, then they will give you a print-out of exactly where it is located. They are only about $25.