Database
db={"vehicles":[{"_id":1,brand:"",model:"",year:"",suppliers:[{"name":"","contact":"","supplierId":"5a934e000102030405000001"}]}],"suppliers":[{"name":"","contact":"","_id":ObjectId("5a934e000102030405000001"),"internalId":"2","address":""}]}
Query
db.vehicles.update({_id:1},{$set:{suppliers:[{"contact":"","internalId":"2","name":"","supplierId":"5a934e000102030405000001"}]}})