How does the 4x4 "Auto" mode actually work?
Certified Thread Hijacker
Joined: Aug 2001
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The 4A setting is awesome. Especially if the surface conditions are constantly changing from dry to snow/ice.
Really nice taking off from stoplights and stop signs too.
The Info screen graphic that shows Power Distribution is quite addictive (in a bad way really) for all those conditions.
Josh
Really nice taking off from stoplights and stop signs too.
The Info screen graphic that shows Power Distribution is quite addictive (in a bad way really) for all those conditions.
Josh
Cargo Master
Joined: Apr 2010
Posts: 3,274
Likes: 4
From: Seattle area
The 4A setting is awesome. Especially if the surface conditions are constantly changing from dry to snow/ice.
Really nice taking off from stoplights and stop signs too.
The Info screen graphic that shows Power Distribution is quite addictive (in a bad way really) for all those conditions.
Josh
Really nice taking off from stoplights and stop signs too.
The Info screen graphic that shows Power Distribution is quite addictive (in a bad way really) for all those conditions.
Josh
I agree the Power Distribution page is very addictive. It's been snowing around here, so getting to use 4A and seeing how everthing works is fun. Have to be careful it's not too distracting.
Senior User
Joined: Jun 2009
Posts: 174
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From: Central Florida
I just clicked mine into 4A this week for the first time. Got some noise in the front like a dry CV joint or bearing. I'll have to get it checked out once I get out of the miserable weather in Michigan and back down in Florida next week.
New User
Joined: Feb 2017
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Random question, but I just used my 4A mode for the first time and was surprised to see a 2 MPG improvement on my gas mileage. Anyone else experience this?
Super Moderator
Joined: Aug 2003
Posts: 25,479
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From: Isanti, MN
Driving conditions are huge when it comes to fuel economy, though. Temperature, wind, and traffic conditions can easily make a 5 MPG difference along a particular route...I think this is much more likely than your use of 4A.
Senior User
Joined: Apr 2007
Posts: 190
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Late to the thread, but yeah, TOD is awesome for that. I had it in my 2000 Isuzu Trooper and it was so great to be able to drive varying conditions (which I do a lot on offroad adventures) without worrying about damaging the 4WD system, or taking a chance on an ice patch or unexpected sand trap while in 2WD. It's the one negative on my 2014 4Runner Trail, as Toyota stopped the two choices for 4WD high on the 5th gen.
I only have the 2WD F150 so wasn't up on the Ford 4WD system. Really glad to see they have this option. Likely by the time I get my next vehicle, I'm going to downsize to just having one. This is actually a big factor that would push me into a 4WD crewcab F150 as the one vehicle.
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Hotshot
Joined: Apr 2013
Posts: 10,120
Likes: 652
From: NH
2HI gives the best fuel economy, because the front end is completely disconnected. 4A is the next best option, because it will only send torque from the engine when slip occurs, and will stop sending torque once the slip condition is corrected. It uses a clutch to rapidly engage and disengage the front driveshaft at the transfer case. Tom, correct me if I'm wrong but if "4A" mode is selected, vacuum is removed from the hubs so they are locked during this time (allowing the drive to be nearly instantly engaged and disengaged by the clutch instead of waiting for hubs to lock / unlock). If I'm correct, this means while in 4A mode, the front end is turning at all times without being connected to the front output of the transfer case...so additional drag and fuel use would result. 4HI would result in the highest fuel consumption, because the clutch on the front of the transfer case is permanently, fully engaged.
In my opinion, 4A definitely would use *more* fuel on dry roads then 2HI because of the front end being in a "ready" state. That is why 2HI is an option. It may not use much more, but a little more. However, 4A may use a tad less fuel than standard locked 4HI because the transfer case is only engaged as needed.
One side note - trucks without 4A mode (XLT and down) don't use a clutch at all...they literally lock the transfer case front output shaft to the driveshaft by a gear engagement. So if you are planning on installing larger tires and rock crawling, an XL, STX, or XLT is definitely the way to go.
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Lead Driver
Joined: Sep 2003
Posts: 5,844
Likes: 6
From: Albuquerque
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2-speed Automatic 4WD System (1)
• Optimizes traction by transferring power to the appropriate wheels when needed
• The system provides four available modes of operation and is activated by using a rotary switch on the instrument panel
2H (HIGH)
• Vehicle operates as a rear-wheel-drive vehicle
when 2H is engaged
• Helps vehicle provide optimal fuel economy
4A (Automatic Four-Wheel Drive)
• Set-and-forget function provides four-wheel-
drive capabilities when needed
• Under normal road conditions, most power is sent to the rear wheels
• As road conditions require, engine torque is sent to the front and/or rear wheels to help maintain optimum traction
• Setting is appropriate for any driving, whether on dry pavement or in adverse conditions
4H (HIGH)
• Setting provides electronically locked four-wheel- drive power to both the front and rear wheels for use at normal speeds on low-traction surfaces
• Intended for use only in severe weather and off- road conditions including snow, ice, sand or mud
• Setting should never be used on dry pavement
4L (LOW)
• Setting provides four-wheel drive with full power to both the front and rear wheels and includes
a lower gear reduction ratio for increased torque multiplication to all four wheels
• Intended only for off-road applications that require extra power including deep sand, steep grades or when launching or pulling a boat out of water
• Setting should never be used on dry pavement
(1) Include on Lariat 4x4 models and above. July 2011.
Quote:
Auburn Hills, Michigan, March 22, 2012 – BorgWarner will supply Torque-On-Demand® (TOD®) two-speed transfer cases for the 2012 Ford F-150 Lariat, King Ranch and Platinum models. The first two-speed active all-wheel drive system for F-150 trucks will feature 4-high, 4-low, full-time and automatic all-wheel drive modes. Built with the same high reliability as its previous part-time shift-on-the-fly transfer cases, BorgWarner’s TOD active all-wheel drive technology delivers improved traction, stability and dynamics. Since 2006, BorgWarner has also produced single-speed TOD transfer cases for the F-150 Harley-Davidson edition.
“BorgWarner’s TOD technology automatically redistributes torque from the rear wheels to the front wheels without driver intervention,” said Joe Fadool, President and General Manager, BorgWarner TorqTransfer Systems. “BorgWarner is pleased to continue our long partnership with Ford, providing F-150 drivers with seamless traction control whether driving off-road or on-highway, in normal or difficult weather conditions.”
The vehicle’s control systems monitor signals such as steering wheel angle, accelerator pedal position and wheel speeds, commanding the TOD transfer case to deliver the required amount of torque to the front and rear axles. With both high and low range capability, drivers will appreciate automatic all-wheel drive benefits in a broad range of driving situations, from normal driving to off-roading to towing. By predicting slip and providing pre-emptive torque, TOD technology improves traction, increases stability and enhances vehicle dynamics. BorgWarner also supplies a number of other technologies for the Ford F-150, including timing drives for all models, variable cam timing phasers for the 5.0-liter Coyote and 6.2-liter Boss engines, HY-VO® chain for models with TOD and part-time transfer cases, friction plates for the six-speed automatic transmission, and turbochargers for the 3.5-liter EcoBoost® engine.
https://www.borgwarner.com/en/news-m...the-ford-f-150
2-speed Automatic 4WD System (1)
• Optimizes traction by transferring power to the appropriate wheels when needed
• The system provides four available modes of operation and is activated by using a rotary switch on the instrument panel
2H (HIGH)
• Vehicle operates as a rear-wheel-drive vehicle
when 2H is engaged
• Helps vehicle provide optimal fuel economy
4A (Automatic Four-Wheel Drive)
• Set-and-forget function provides four-wheel-
drive capabilities when needed
• Under normal road conditions, most power is sent to the rear wheels
• As road conditions require, engine torque is sent to the front and/or rear wheels to help maintain optimum traction
• Setting is appropriate for any driving, whether on dry pavement or in adverse conditions
4H (HIGH)
• Setting provides electronically locked four-wheel- drive power to both the front and rear wheels for use at normal speeds on low-traction surfaces
• Intended for use only in severe weather and off- road conditions including snow, ice, sand or mud
• Setting should never be used on dry pavement
4L (LOW)
• Setting provides four-wheel drive with full power to both the front and rear wheels and includes
a lower gear reduction ratio for increased torque multiplication to all four wheels
• Intended only for off-road applications that require extra power including deep sand, steep grades or when launching or pulling a boat out of water
• Setting should never be used on dry pavement
(1) Include on Lariat 4x4 models and above. July 2011.
Quote:
Auburn Hills, Michigan, March 22, 2012 – BorgWarner will supply Torque-On-Demand® (TOD®) two-speed transfer cases for the 2012 Ford F-150 Lariat, King Ranch and Platinum models. The first two-speed active all-wheel drive system for F-150 trucks will feature 4-high, 4-low, full-time and automatic all-wheel drive modes. Built with the same high reliability as its previous part-time shift-on-the-fly transfer cases, BorgWarner’s TOD active all-wheel drive technology delivers improved traction, stability and dynamics. Since 2006, BorgWarner has also produced single-speed TOD transfer cases for the F-150 Harley-Davidson edition.
“BorgWarner’s TOD technology automatically redistributes torque from the rear wheels to the front wheels without driver intervention,” said Joe Fadool, President and General Manager, BorgWarner TorqTransfer Systems. “BorgWarner is pleased to continue our long partnership with Ford, providing F-150 drivers with seamless traction control whether driving off-road or on-highway, in normal or difficult weather conditions.”
The vehicle’s control systems monitor signals such as steering wheel angle, accelerator pedal position and wheel speeds, commanding the TOD transfer case to deliver the required amount of torque to the front and rear axles. With both high and low range capability, drivers will appreciate automatic all-wheel drive benefits in a broad range of driving situations, from normal driving to off-roading to towing. By predicting slip and providing pre-emptive torque, TOD technology improves traction, increases stability and enhances vehicle dynamics. BorgWarner also supplies a number of other technologies for the Ford F-150, including timing drives for all models, variable cam timing phasers for the 5.0-liter Coyote and 6.2-liter Boss engines, HY-VO® chain for models with TOD and part-time transfer cases, friction plates for the six-speed automatic transmission, and turbochargers for the 3.5-liter EcoBoost® engine.
https://www.borgwarner.com/en/news-m...the-ford-f-150
Great Information!
biz
Thread Starter
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Hotshot
Joined: Apr 2013
Posts: 10,120
Likes: 652
From: NH
It is, but not totally correct. On this system, "4HI" is not a physical lock. It just fully engages the clutch. Additionally, in 4A mode, *all* of the torque is sent to the rear wheels until slippage occurs. Otherwise, the clutch would burn out. It really is a good system though...reacting extremely quickly and nearly mirroring the way full-time 4WD works...but without the center differential.
Super Moderator
Joined: Aug 2003
Posts: 25,479
Likes: 742
From: Isanti, MN
Originally Posted by troverman
Additionally, in 4A mode, *all* of the torque is sent to the rear wheels until slippage occurs. Otherwise, the clutch would burn out. It really is a good system though...reacting extremely quickly and nearly mirroring the way full-time 4WD works...but without the center differential.
You can even watch the power transfer on the information screen on the F150 and most of the other Ford AWDs. My current Escape applies power to the rear axle at all times below 25 MPH, as well as whenever I ask for strong acceleration. My soon-to-be ex-wife's clutch-based AWD Sienna would do the same thing.
Lead Driver
Joined: Sep 2003
Posts: 5,844
Likes: 6
From: Albuquerque
It is, but not totally correct. On this system, "4HI" is not a physical lock. It just fully engages the clutch. Additionally, in 4A mode, *all* of the torque is sent to the rear wheels until slippage occurs. Otherwise, the clutch would burn out. It really is a good system though...reacting extremely quickly and nearly mirroring the way full-time 4WD works...but without the center differential.
However, in 4-Lo and 4-Hi, it is technically "locked". Because the clutch mechanism (primary and secondary) will not slip due to the magnetic force applied. Or better said, should not slip.
I understand it is not locked as in gear to gear.
Do we know what model (the number) the BW-TOD transfer case is??
biz
Postmaster
Joined: Feb 2014
Posts: 4,735
Likes: 1
From: Hattiesburg, Ms.
Not sure of all the particulars, but it works really well in inclement weather. You can pull up the torque distribution screen and watch it swap power to where it's needed, it does it seamlessly. Real handy down here in monsoon season, especially with all the ruts in the highway from log trucks and whatnot (cheap *******s won't fix the roads!)
Thread Starter
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Hotshot
Joined: Apr 2013
Posts: 10,120
Likes: 652
From: NH
This part isn't true, there are plenty of situations when the front axle gets power without wheel slippage. All of Ford's clutch-based AWD systems do this, as does almost all competing brands.
You can even watch the power transfer on the information screen on the F150 and most of the other Ford AWDs. My current Escape applies power to the rear axle at all times below 25 MPH, as well as whenever I ask for strong acceleration. My soon-to-be ex-wife's clutch-based AWD Sienna would do the same thing.
You can even watch the power transfer on the information screen on the F150 and most of the other Ford AWDs. My current Escape applies power to the rear axle at all times below 25 MPH, as well as whenever I ask for strong acceleration. My soon-to-be ex-wife's clutch-based AWD Sienna would do the same thing.
Thanks. I guess it makes sense to certain situations (such as moderate to full throttle inputs) to engage the clutch to a degree to preemptively prevent wheel slip. Our Lincoln MKS (with 3.5L EcoBoost and AWD) seems like it does not add in the rear wheels until slip does occur...there is hard torque steer if you floor it on takeoff for a moment.
Thread Starter
|
Hotshot
Joined: Apr 2013
Posts: 10,120
Likes: 652
From: NH
However, in 4-Lo and 4-Hi, it is technically "locked". Because the clutch mechanism (primary and secondary) will not slip due to the magnetic force applied. Or better said, should not slip.
I understand it is not locked as in gear to gear.
Do we know what model (the number) the BW-TOD transfer case is??
biz
I understand it is not locked as in gear to gear.
Do we know what model (the number) the BW-TOD transfer case is??
biz