diff --git a/src/directives/internal/transition.js b/src/directives/internal/transition.js
index 6815a2bd87f..0069567fcf3 100644
--- a/src/directives/internal/transition.js
+++ b/src/directives/internal/transition.js
@@ -13,9 +13,7 @@ export default {
     id = id || 'v'
     oldId = oldId || 'v'
     el.__v_trans = new Transition(el, id, hooks, this.vm)
-    if (oldId) {
-      removeClass(el, oldId + '-transition')
-    }
+    removeClass(el, oldId + '-transition')
     addClass(el, id + '-transition')
   }
 }