Just finished my Durga BUT have a problem (I think)

. I am running it stock as per the build manual with a black can Sport Tuned (17T pinion) just to bed everything in. I have the slipper clutch - set to 3mm - and have shimmed the layshaft to get rid of the end float. All the screws are tight and the pinion/spur mesh is set to give a tiny bit of play the same as I have always run my RC10 B4. The 'problem' is that the drivetrain sounds like someone has thrown a load of gravel in it - it feels OK vibration wise but the best way I can describe it is like a straight-cut car gearbox, ie loud and rough

. Is this normal?
I am running Tamiya CVD's front and rear and they are OK, no play etc.
Jimmy's didn't seem to make any noise at all on Sunday and I am now worried that it'll rip itself to bits when I put the brushless in it.