There is one underneath the van (driver's side) and one on top of the engine. If you google it you should find the info you need. The TransferFlow tank doesn't change anything about stock filters.
To get to the one on top of the engine you need to take screws out that are holding the harness above the engine and pull it up and out of the way. I use a bungee to hold it up and out of the way. For the one under the van you need to drain first with the valve on the bottom of the filter.
It's not a bad project to do.
- 2005 EB50 6.0PSD - SMB 4x4