I changed mine by placing a jack under the transmission, removing the trans mount and lowering the rear of the transmission a little
the flex disk didn't fall out but with a little coaxing with a long screwdriver it dropped out. The new one was relativly easy to put in and raising the trans as I put it in held it in place.
All totaled it took me about 1 1/2 hours to replace it. Just be carefull not to damage anything at the rear of the engine as you lower the trans. This was a couple of years ago but I don't think that I lowered it more than a couple of inches. Getting the bolts loose was the hardest part as they had sucked into the flexdisk
a little and were pretty chewed up. New bolts came with the Flexdisk I got from Fastlane.

__________________
Dave
88 300E 250K Sold
2000 C230K Totaled @104K
2003 ML320 156K Sold
2009 E350 4Matic Sport 46K Sold
2011 ML350 60K Sold
2014 GLK350 46k Sold
2012 GL450 72K For Sale
2016 E550 Cabriolet 48K Sold
2015 GLK350 114K