Brother DCP-L8400CDN Service Manual page 313

(13) Release the Hook and remove the Fuser drive gear Z25 from the Process drive unit.
Hook
Fuser Drive Gear Z25
Process drive unit
Fig. 3-207
Harness routing: Refer to " Laser Unit", " Process Drive Unit, Front Cover Sensor,
Main Drive Unit", " Develop Release Drive Unit, Develop Release
Sensor PCB ASSY, Toner/New Sensor PCB ASSY", " MP Paper
Empty/Registration Front Sensor PCB ASSY", " Paper Feed Unit"
3-149
Confidential