L322 Range Rover System Description and Operation
TRANSFER BOX
DESCRIPTION AND OPERATION
41-21
1 Spare 5A fuse
2 Fuse 37
To engage the transfer box in neutral, switch the ignition to position II and select neutral 'N' on the transmission
selector lever. Insert a spare 5 Ampere fuse or greater into the empty fuse position 37 in the passenger compartment
fusebox, which is located at the back of the glovebox. Fuse position 37 can be identified using the legend on the
fusebox cover.
Once the fuse is installed, the actuator will engage the transfer box in the neutral position.
Once in neutral, the low range 'mountain' symbol in the instrument pack flashes permanently and 'TRANSFERBOX
NEUTRAL' is displayed in the instrument pack message centre.
Cold Climate Operation
In low ambient temperatures, there may be an increased time delay for the transmission to select neutral. To prevent
the transfer box changing range before the transmission has selected neutral, the transfer box ECU contains software
to delay the range change.
The transfer box ECU receives a transmission fluid temperature message on the CAN. If this temperature is 5
°
C
(41
°
F) or below, the transfer box ECU initiates a nominal delay in the range change to allow the transmission to
engage neutral. The delay period is dependant on transmission fluid temperature.
High Range Operation
In high range, the torque input from the transmission is passed to the transfer box input shaft. The position of the
synchroniser sleeve couples the shaft directly to the differential housing. The differential splits the torque between the
two side gears. One side gear is connected by splines and passes the torque to the rear output flange. The second
side gear is connected to the chain drive sprocket and passes the torque, via the chain, to the front output flange.
Low Range Operation
In low range, the torque input from the transmission is passed to the transfer box input shaft. The synchroniser sleeve
is moved and connects the planetary carrier to the differential housing. The torque from the transmission is now
directed through the sun gear of the epicyclic gearset and, via the pinion gears and pinion gear shafts, into the
planetary carrier. The annulus gear of the epicyclic gearset is secured inside the casing and generates the low range
ratio of 2.69:1. The torque is then passed, via the synchroniser sleeve, to the differential housing where it is split
between the two side gears. One side gear is connected by splines and passes the torque to the rear output flange.
The second side gear is connected to the chain drive sprocket and passes the torque, via the chain, to the front output
flange.