Jakes while down shifting and up shifting. Alot of rev matching and perfect shifting. ts a 400HP 60 series Detroit, 1996 Freightliner, 390ratio... 1996, 39ton 42ft flatbed Channel IVSJA - http://www.youtube.com/user/IVSJA?feature=watch Video - http://www.youtube.com/watch?v=JTfpb5xWk2w