@Frank22 when you export with zmodeler 3 make sure parent dummy has the same name you are trying to export the file with .
meaning if parent dummy is named JEEP1 export file with name Jeep1 and it will get exported. but there are other things to take care of as well, as to parent must have chassis dummy and then everything should be child to the chassis dummy. and chassis dummy is child to jeep1 dummy.
but exporting this file to yft will not benefit you as this file can't be used in gta 5. it needs to be properly rigged in zmodeler 3 for it to work in gta 5. it will most likley crash ur game. you need to visit zmodeler 3 forums and learn stuff there. people here might nto be able to help you out.
Ok Thank you !!