If you have paid in full for the vehicle and there is no mortgage on the vehicle, yes you can sell it.
I have experienced for the past 40 years that Sheriff deputies are not very diligent. They are not cheap, but there are private process servers that will ask you for his patterns. They can serve anywhere-work, a bar or anywhere else. However, in Georgia in most counties, the judge must appoint a process server by petition and order.
You need to contact HR at his employer and advise and give documentation that he gave them false information. You need to send them a certified copy of settlement and final order to document this. Then you need to hire an attorney to prepare a Qualified Domestic Relations Order which recognizes and sets out your benefits. It will be sent to the employer which will have to abide by it..
If the parties and this property is in Georgia the contributions of the parties will be compared that took place during the marriage as well as equity of owner before marriage and compared for equitable division.