Still waiting on parts for the transmission - using the E60 M5 as daily driver but that's in at Winger today for O2 sensor and thermostat replacement to deal with stalls occurring when idling.
Here's the summary of what Zane found:
BMW X5 V8 Reg JHC777 236744 KMs
Transmission fault : leaking oil from front of transmission. Remove exhaust , covers, drive shaft, part of suspension to enable removal of transmission. Disassemble transmission clean & check. Convertor lockup lining has broken up causing damage to front pump housing, gears & convertor neck. Clutch packs showing signs of burning. Bearings through hardening.
Ouch! Total cost to me for rebuild after Autosure max claim on old high km vehicle = ~$4500
Just saw this 4.8is come up for sale not far away... tempting (I think? ) https://www.trademe.co.nz/Browse/Listing.aspx?id=1836240753