Вы можете настроить свой переход, используя CATransition
CATransition *animation = [CATransition animation];
animation.delegate = self;
animation.duration = 0.25f;
animation.timingFunction = UIViewAnimationCurveEaseInOut;
animation.fillMode = kCAFillModeForwards;
animation.removedOnCompletion = NO;
animation.type = kCATransitionPush;
animation.subtype = kCATransitionFromTop;
[YourView.view.layer addAnimation:animation forKey:@"animation"];
[self.view addSubview:bView];