I checked the level only yesterday and it is up to the full mark. The 'surging' has now become a 'juddering' accompanied by a screeching noise so if you get any good ideas (or even half good), please let me know!
My '99 F Steptronic 'surges' when I am trying to move slowly such as when I am parking. This happens in both drive and reverse. It also engages drive and reverse with a definite 'clunk'. Otherwise it works fine. The tick over is correct as is the fluid level. The fluid and filter have recently been renewed which, initially, significantly improved the performance of the box. Any Ideas?