Can I take my ex. To court for being late for car payments while the car is in his possession ?

Yes.  You have a contract by which you agreed to let your ex use the car in exchange for his agreement to make any continuing payments.  He has breached the contract, and you can sue him for damages you sustain as a direct result, i.e. if you have to make the payments (you are still liable to the car company) or if you lose the car. Your problem is one of proof.  If the contract is characterized as one in which you sold the car to your ex (as opposed to one in which didn't sell the car, but only allowed your ex to use it for a time, as long as that time could have been less than a year) , many states will require such an agreement to be in writing (in most American jurisdictions, a contract for the sale of goods for over $500or a contract which cannot be fully performed within a year, must be in writing).  You don't say whether you have any writing proving the agreement with your ex.  Even if the agreement is not required to be in writing, it is possible, depending on the evidence, that a court will not believe you, but rather will believe your ex if he says that he did not agree to make the payments. Even if you can't prove that you had a contract for your ex to take over all payments, the Court will likely require him to pay for the time he has used the car, probably in the amount of the payments which were due during that time. Unfortunately, it sounds like your ex may not have any money to pay you, even if you win the lawsuit, but you may at least be able to compel him to return the car to you.