I notice a definite harsh vibration at the rear while defending while the engine deceleration is functioning. I believe that I read a post about this coming from the heat shroud because of the 'cheap ' hose clamps. However I don't notice this on a similarly new Kodiac 450. Any ideas before I embarrass myself taking it in for nothing? By the way the engine braking on the 450 is simply superb. Am thrilled with the Kodiacs all round excellence. Will work them very hard..but no mud holes or submarine activity for me. L lets go climb some hills.