The oil was changed in 2016 and performed perfectly until 2024 when the car was scrapped due to catastrophic rust. Quite a long film on how I successfully changed the transfer box oil on my 2001 X Type 2.5 V6 Manual Petrol on the drive with no special tools, connectors or pumps. You need a 2 tonne jack, axle stands, 3/8th driver, a funnel, garden hose and some new oil. Update for Jan 2023 - still running as smooth as silk. All those people worried about the bricks I used - they are new engineering bricks used to build the plinth of my house.