Audiparts2010

Hi all in need of a little help I've recently drained the auto trans oil out of my c220 cdi only from the sump and removed the sump and filter and replaced the sump wit new filter and seal.after speaking to local mb dealer I've refilled with 8 litres of oil.and now it leaks like mad.
Can anyone tell me how much oil it's meant to have as I'm sure it's got to much in but can't be sure as I haven't got a dipstick.
All help much appreciated.