I have a Alphard AH20 with CVT transmission. When accelerating the engine revs suddenly jump eg 1100 to 2800 then drops back to 1600 approx. Its as though the box was slipping. I am sure as my local mechanic the box is not slipping.will climb 45 degree slope no problems even on longer inclines will change up no problem. Any help where I can go next would be appreciated. Even point me in the direction of a good expert in Scotland. Local Toyota garage has only one option replace gearbox and see if this helps.