What is the religious ruling on a car in the wife's name for which the husband paid the down payment, and he uses it and refuses to sell it except by taking half the amount?

If the husband bought the car and gifted it to his wife, and he paid its down payment while she kept it, then it is her property, especially since she paid the remaining installments. She has the right to dispose of it as she wishes, and the husband has no right to demand half the amount. However, if the wife was the one who bought it or appointed her husband to buy it on her behalf, it is also her property, but the value of the installment paid by the husband is considered a debt owed to him by her, unless he had gifted it to her.