308-07A Four-Wheel Drive Systems: Description And Operation (page 28 of 30)

 
The range change process can take up to one second to complete following a request being accepted. 
 
There is a limit set on the maximum speed at which a range change can be achieved. The maximum speed for a high to 
low range change is 25 mph (40 km/h) for vehicles with automatic transmission, and 12 mph (20 km/h) for vehicles with 
manual transmission. The maximum speed for a low to high range change is 37 mph (60 km/h). If the vehicle speed is 
over the limit when a range change is selected then the request is denied and the instrument cluster message centre (if 
fitted) will display a 'SLOW DOWN' message. 
 

RANGE CHANGE PROCEDURE (MANUAL VEHICLES ONLY) 

Neutral must be selected on the main transmission before requesting a range change and then select the appropriate 
gear following completion of the range change. During the range change the driver must not attempt to move the main 
transmission out of neutral. If the lever is moved out of neutral then the range change will stop and will be completed only 
when the driver re-selects neutral on the main transmission. This must be done to prevent damage to the transfer box 
mechanism. 
 
The speed limit for shift-on-the-move for the manual vehicle is set lower than for the auto, at around 12 mph (20 km/h) for 
high to low and 37 mph (60 km/h) for low to high. The lower limits are set so that, if the driver tries to select too lower gear 
following a range change, no damage is caused to the vehicle. 
 

TRANSFER BOX CONTROL DIAGRAM 

NOTE :  

A = Hardwired; D = CAN bus