diff --git a/sync.m b/sync.m
index 63f78e1..69a39e3 100644
--- a/sync.m
+++ b/sync.m
@@ -95,7 +95,7 @@ static void deallocLockClass(id obj, SEL _cmd)
 	// Call the real -dealloc method (this ordering is required in case the
 	// user does @synchronized(self) in -dealloc)
 	struct objc_super super = {obj, realClass };
-	objc_msgSendSuper(&super, SELECTOR(dealloc));
+	objc_msg_lookup_super(&super, SELECTOR(dealloc))(obj, SELECTOR(dealloc));
 	// After calling [super dealloc], the object will no longer exist.
 	// Free the lock
 	mutex_t *lock = object_getIndexedIvars(lockClass);