1979 F150

Can you shift into 4x4 on the fly and up to what speeds, also what is the max speed while in 4x4 high? Thanks

Platinum_Sean

Start at page 296: Click here.

1979 F150

The link is not working.

big_ole_truck

Shifting into 4x4 LO can only be done at a complete stop but you can switch in and out of 4x4 HI up to 45 mph (or was it 55 mph?). It's in the owner's manual.

myowneq

I don't think you can shift into 4lo at a dead stop. I seem to remember I was unable to do it. You can shift at any speed at any time. The computer will decide when the shift happens.

From 2x to 4Hi and back, I did it at 20mph. I just stayed off the gas during the shift. Cruised on a dirt road up to 45mph.

As for 4 lo, dash says slow to 3mph to shift. If the shift doesn't happen, gotta speed up again. Shifting out of is the same way. slow to 3mph.

Platinum_Sean

Try this one: http://www.motorcraftservice.com/pub.../09f12og3e.pdf

OD52

Using a manual 4WD system (if equipped)

2H (4X2) – Power to the rear wheels only; used for street and highway
driving. Provides optimal smoothness and fuel economy at high speeds.

4H (4X4 High) – Used for extra traction such as in snow or icy roads or
in off-road situations. Not intended for use on dry pavement.

N (Neutral) – No power to either front or rear wheels.

4L (4X4 Low) – Uses extra gearing to provide maximum power to all
four wheels at reduced speeds. Intended only for off-road applications
such as deep sand, steep grades or pulling heavy objects. The shift lever
will not engage 4L (4X4 LOW) until the transmission is in N (neutral)
and the vehicle is moving below 3 mph (5 km/h); this is normal and
should be no reason for concern. Refer to Shifting to/from 4L (4X4
Low) for proper operation.

Shifting between 2H (4X2) and 4H (4X4 high)

• Move the transfer case lever between 2H (4X2) and 4H (4X4 High) at
a stop or any forward speed.
Note: Momentarily releasing the accelerator pedal while preforming a
shift will improve engagement/disengagement times.
Note: Do not perform this operation if the rear wheels are slipping.
Note: Some noise may be heard as the system shifts or engages; this is
normal.

Shifting to/from 4L (4X4 Low)

1. Bring the vehicle to a speed of 3 mph (5 km/h) or less.
2. Place the transmission in N (Neutral).
3. Move the transfer case lever through N (Neutral) directly to the
desired position.

• If the transfer case will not engage into 4L (4X4 Low) do not force
the lever. Allow the vehicle to coast at a speed below 3 mph
(5 km/h), then repeat Steps 2 and 3.

Note: Some noise may be heard as the system shifts or engages; this is
normal.
Note: For proper operation in 4X4 Low, ensure the transfer case shift
lever is moved entirely rearward in to the 4L (4X4 Low) position and
that the 4x4 Low light is displayed in the message center.
Note: Ideal 4L (4X4 Low) shift conditions occur when the vehicle is
rolling at a speed below 3 mph (5 km/h) and the transmission is in N
(Neutral).

Using the N (Neutral) position

The transfer case N (Neutral) position overrides the transmission
and puts the vehicle in neutral regardless of transmission
gearshift lever position. The vehicle can move forward or
backward.
This position should only be used when towing the vehicle.
WARNING: Do not leave the vehicle unattended with the
transfer case in the N (Neutral) position. Always set the parking
brake fully and turn off the ignition when leaving the vehicle.

OD52

Using the electronic shift 4WD system (if equipped)


2H (4X2 High) - Power to the rear wheels only; used for street and
highway driving. Provides optimal smoothness and fuel economy at high
speeds.


4H (4X4 High) - Used for extra traction such as in snow or icy roads or
in off-road situations. Not intended for use on dry pavement.


4L (4X4 Low) - Uses extra gearing to provide maximum power to all
four wheels at reduced speeds. Intended only for off-road applications
such as deep sand, steep grades or pulling heavy objects. 4L (4X4 Low)
will not engage while the vehicle is moving above 3 mph (5 km/h); this is
normal and should be no reason for concern. Refer to Shifting to/from
4L (4X4 Low) for proper operation.

Shifting between 2H (4X2 High) and 4H (4X4 High)

• Move the 4WD control between 2H (4X2 High) and 4H (4X4 High) at
any forward speed.
The message center will display 4X4 SHIFT IN PROGRESS during the
system shift. “4X4 HIGH” will display in the message center.


Note: Momentarily releasing the accelerator pedal while preforming a
shift will improve engagement/disengagement times.
Note: Do not perform this operation if the rear wheels are slipping.
Note: Some noise may be heard as the system shifts or engages; this is
normal.

Shifting to/from 4L (4X4 Low)

1. Bring the vehicle to a speed of 3 mph (5 km/h) or less.
2. Place the transmission in N (Neutral).
3. Move the 4WD control to the desired position.

The message center will display 4X4 SHIFT IN PROGRESS during the
shift. The message center will then display the system mode selected.
If any of the above shift conditions are not met, the shift will not occur
and the message center will display information guiding the driver
through the proper shifting procedures.


If 4X4 SHIFT IN PROGRESS is displayed for more than five
seconds, transfer case gear tooth blockage is present. To alleviate
this condition, move the vehicle forward approximately five feet
(2 meters) to allow the transfer case to complete the shift.
Note: Some noise may be heard as the system shifts or engages; this is
normal.

SFCFX4

So according to that^^^^^, you can shift into 4H at any speed? I was under the impression that it was usually said in any 4wd vehicle to not shift at speeds greater than 55 mph.

dpeckford

I can't think of any situation where I personally would need to shift into four wheel drive at speeds greater than 55 mph. If it is that slippery perhaps it would be prudent to slow down a bit first ??