Chevrolet 1979 Light Duty Truck Owner's Manual page 41

VEHICLE MOVING
The transfer case can be Shifted without depressing the clutch and with the understanding that the transfer case ratio is approximately 2:1 you should be able to do this with ease.
ratio of 2:1 means that your engine speed must be doubled if shifting from either 2H or 4H to 4L as the shift lever is moved through Neutral. If shifting from 4l to 2H or 4H
A
the engine must be allowed to coast (as the shift lever is moved through Neutral) to half its original speed. Never shift to 4L at a speed above 10 m.p.h.
NOTE: It may be necessary to lift your foot from the throttle in order to move the shift lever to the Neutral position.
TO SHIFT TRANSFER CASE FROM
4L (Low Range)
2H or 4H ( H igh Range)
';->
-
2H (Rear Wheel Drive)
4H (All Wheel Drive)
VEHICLE STATIONARY
TO SHIFT TRANSFER CASE FROM
Neutral
Any Position
Any Position
SHIFTING PROCEDURE FOR CONVENTIONAL (PART-TIME) FOUR WHEEL DRIVE
NOTE: Tbe transfer case selector placed in 2H (2 wheel drive High Range) position for normal driving.
is
TO
2H or 4H ( H igh Range)
(Use 4H on low traction
road surface only).
4L (Low Range)
( Used on low traction
road surface only).
4H (All Wheel Drive)
( Used for low traction
road surface only).
2H ( R ear Wheel Drive)
TO
Any driving position
Neutral
4L (All Wheel Drive)
( Used for low traction
road surface only)
PROCEDURE
1. With clutch engaged, momentarily release accelerator pedal while shifting transfer
case from Low Range to Neutral.
2. Depress accelerator pedal to provide one-half ol original engine speed.
3.
Shill transfer case lever from Neutral to 2H or 4H (H igh Range).
1. Make shift at speed of 10 MPH or less. ( F ront axle hubs must be locked).
2. With clutch engaged, momentarily release accelerator pedal while shifting transfer case
from High Range to Neutral.
3.
Depress accelerator pedal to double engine speed.
4. Shift transfer case l ever from Neutral to 4L ( Low Range).
1. May be made at any speed, forward or reverse with front axle hubs locked.
2. Move lever into position.
1. May be made at any forward or reverse speed.
2. Release accelerator pedal momentarily.
3.
Shift into position.
PROCEDURE
1.
Depress clutch pedal.
2. Wait momentarily for gears to stop if engine is running.
3.
Shift all the way into desired drive position.
1. Depress clutch pedal.
2. Shift transmission into Neutral.
3.
Shift transfer case lever to Neutral.
1. Front axle hubs must be locked.
2. Depress clutch pedal.
3.
Move control lever fully into position.