Can i file a writ of possession to get my truck back from a ex husband

Have been divorced for three years but ex and i got back together for two years i bought a new truck last year let him drive it if he made payments. Signed a paper stating he could drive it if he made payments and paid off then i would sign over to him it is not notorized plus i do not remember saying i would give to him. He moved out and took truck with him. I have ask him to bring home or put in his name. Four months no answer he is making payments late hurting my credit. Have been told he is on drugs, his new girlfriend is meth head. Can i file a writ of possessio to get it back?