4x4 4A
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4x4 4A
When should I be using this?
I understand 4L is for the really nasty stuff at crawl speed, 4H is for off road when going a bit quicker (maybe in sand), but where does 4A fall?
Is this okay to use on pavement when it is pouring rain?
Your guidance on this matter is appreciated!
I understand 4L is for the really nasty stuff at crawl speed, 4H is for off road when going a bit quicker (maybe in sand), but where does 4A fall?
Is this okay to use on pavement when it is pouring rain?
Your guidance on this matter is appreciated!
It also seems to kick in on acceleration from stop then drops back to RWD when you're up to speed, even on dry roads. I've only confirmed this 2 or 3 times by looking at the power distribution on the cluster screen while in 4A.
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I won't swear to this, but base my comment on older models with this option.
If you look on the inside of the brake hub on front wheels you will see a small ring around the drive axle. At the top there is a tube with two connecting points to a vacuum line. On the inside of this "ring" is a gear. When in 4x4 (H, L or A) there is vacuum to this ring. The vacuum forces the ring to engage the gear which connects the axles and drive gear to the transfer case. IOW this is the way Ford disconnects the front drive assembly when in 2x4 drive, increasing fuel economy by not "dragging" the front gears and axles.
Previously (not sure about the new models) there was a clutch pack in the transfer case that routed a specific percentage of the torque to the front (used to be 35%) when in "auto." If slippage was detected between the front and rear axles additional torque was ratcheted to the front drive wheels to some maximum percentage.
Three things:
- If you are driving in auto you are dragging/driving the entire front drive train.
- Your fuel economy will go down accordingly, probably 2+ MPG
- Because of the clutch pack you can drive in auto all the time, even on hard pavement.
The best thing about auto is the ability to not to have to switch back and forth between 2x4H and 4x4H when roads are partially snow/mud packed. For instance when diving on 100% snow then run into an area where the road is clear. Unlike 4x4H, the clutch pack prevents binding in the drive train and auto takes the guess work out of when to select one mode over the other.
Should you use it when it's raining? Short answer - no, not unless it's raining so hard there is a strong possibility of hydroplaning.
This brings the question of the locking rear axle. I installed the same system on my current pick-up. I've only used it 2-3 times since installation and only when stuck, trying to get out of a jam, AND going straight. If you want LESS traction leave it on - a slipping tire has less friction with the surface than an non-slipping tire and when turning the inside wheel will slip. To see what I mean turn it on and do a "U" turn on pavement.
How does it work. There is a circular magnet inside the rear diff. When energized by pulling out on your 4x4 selector, the magnet is drawn to a steel ring. On the other side of the ring are 3 (or 4) steel *****, each having their own ramp in the ring. The magnetic force causes the ***** to ride up on their respective ramp causing a ring of steel pins to be pushed away from the steel ***** and each pin engaging a hole in the opposite axle, locking the diff.
Like I said, I've only used mine 2-3 times, when pulling someone out, or to keep myself from getting stuck when it's close and I'm going very slow. It can get quite squirrelly otherwise so be careful if you leave it engaged on snowy or icy roads.
If you look on the inside of the brake hub on front wheels you will see a small ring around the drive axle. At the top there is a tube with two connecting points to a vacuum line. On the inside of this "ring" is a gear. When in 4x4 (H, L or A) there is vacuum to this ring. The vacuum forces the ring to engage the gear which connects the axles and drive gear to the transfer case. IOW this is the way Ford disconnects the front drive assembly when in 2x4 drive, increasing fuel economy by not "dragging" the front gears and axles.
Previously (not sure about the new models) there was a clutch pack in the transfer case that routed a specific percentage of the torque to the front (used to be 35%) when in "auto." If slippage was detected between the front and rear axles additional torque was ratcheted to the front drive wheels to some maximum percentage.
Three things:
- If you are driving in auto you are dragging/driving the entire front drive train.
- Your fuel economy will go down accordingly, probably 2+ MPG
- Because of the clutch pack you can drive in auto all the time, even on hard pavement.
The best thing about auto is the ability to not to have to switch back and forth between 2x4H and 4x4H when roads are partially snow/mud packed. For instance when diving on 100% snow then run into an area where the road is clear. Unlike 4x4H, the clutch pack prevents binding in the drive train and auto takes the guess work out of when to select one mode over the other.
Should you use it when it's raining? Short answer - no, not unless it's raining so hard there is a strong possibility of hydroplaning.
This brings the question of the locking rear axle. I installed the same system on my current pick-up. I've only used it 2-3 times since installation and only when stuck, trying to get out of a jam, AND going straight. If you want LESS traction leave it on - a slipping tire has less friction with the surface than an non-slipping tire and when turning the inside wheel will slip. To see what I mean turn it on and do a "U" turn on pavement.
How does it work. There is a circular magnet inside the rear diff. When energized by pulling out on your 4x4 selector, the magnet is drawn to a steel ring. On the other side of the ring are 3 (or 4) steel *****, each having their own ramp in the ring. The magnetic force causes the ***** to ride up on their respective ramp causing a ring of steel pins to be pushed away from the steel ***** and each pin engaging a hole in the opposite axle, locking the diff.
Like I said, I've only used mine 2-3 times, when pulling someone out, or to keep myself from getting stuck when it's close and I'm going very slow. It can get quite squirrelly otherwise so be careful if you leave it engaged on snowy or icy roads.
Last edited by Jimja; Apr 1, 2015 at 07:48 PM.
