D4 Auto Box removal - advice please
 

Have a 2017 S90 which I am rebuilding after a front end shunt. The starter motor must have take a knock as there is a 1" crack in the bell housing next to one of the starter retaining bolts. Does anyone have any advice on the best way to replace the bell housing? Engine out, gearbox out or both together, from above or below? Its a D4 engine with the auto box and I have a ramp, would like to keep AC system intact if possible. There is not much info out there on these newer models.
Any hints or tips much appreciated.
Thanks, Rob

Need to put this in general section for a reply

Thanks, have done as suggested.
Cheers, Rob