Sounds fishy, try to get him to do things your way. Maybe let you talk to the shipper, and have the shipper only pick up the car once his check has cleared. Just let him know you are EXTREMELY nervous about this type of transaction, and the only way you'll do it, is if you absolutely, 100% know that you have the cash before you release the car. Just be as careful as possible about it, try to see any way that he could scam you, as there are tons of different methods. Basically, take as much control as you can over it.
