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Limited AWD vs Platinum 4WD Drivetrain

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Smitdog

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So despite inconsistent descriptions of the various drivetrains in the F150 literature, it would appear that at least in the higher trim levels there is a "4A" mode in addition to a "4H" mode, and the Limited drivetrain is not anything unique or special that isn't available in the lower trim levels.

Given that "4H" mode is full-time 4WD (torque applied evenly to all wheels at all times), I'm still trying to understand exactly how "4A" mode operates. Does it apply specific and only as needed torque to individual wheels / axles?
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I think the 4a mode is just a transfer case with a differential.
4x4 of eras long gone had a different TC internally between automatics and standards.
If you were to remove the front shaft on a truck with an automatic and put the TC in 4Hi ( full time 4x4 as they did not have a 2-hi) you would go nowhere.
If you put the TC in 4-hi lock, you could move.
Never could understand why people would put locking hubs on these trucks, because you would have to leave the TC in 4-hi lock all the time.
And that is why I believe the 4A has a differential in the TC similar to the oldies
 
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Near as I can tell from reading other info online, the 4A mode applies torque to the front axle as a whole and "as needed" to help with traction, but does not apply torque to individual wheels based on individual wheel traction availability.

So if that's the case, then when using 4A and making turns on a snow covered parking lot, you would still get the occasional front end chatter as both front wheels are still getting equal amounts of torque applied. This would be the same case as when in 4H mode, except that in 4A mode the transfer case can modulate the application of torque to the front axle better, so likely the chattler will be reduced if not nearly eliminated. And the bonus is that when in 4A mode making tight turns on dry pavement, no torque will be applied to the front axle, so no chatter/binding issues. Sound right?
 

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There is a lot of information here. I think this is a spot where @Granger Ford could help sort this out. Here is what I was told last spring by a Ford rep (in regards to a 2020):

- When Platinum is in 4A, the truck will operate in RWD/2WD until the computer recognizes a condition where it needs more traction or conditions warrant the truck sending power to the front wheels. If you are in a condition where you need 4WD, switch to 4H or 4L on the dial, as 4A is not meant to be used off-road.

-When Limited is in 4A, the truck will operate in AWD by sending power to all the wheels. It has a different transfer case setup than any other F-Series (except Raptor). Same holds true with 4H and 4L, if you need them, switch to them.
 
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There is a lot of information here. I think this is a spot where @Granger Ford could help sort this out. Here is what I was told last spring by a Ford rep (in regards to a 2020):

- When Platinum is in 4A, the truck will operate in RWD/2WD until the computer recognizes a condition where it needs more traction or conditions warrant the truck sending power to the front wheels. If you are in a condition where you need 4WD, switch to 4H or 4L on the dial, as 4A is not meant to be used off-road.

-When Limited is in 4A, the truck will operate in AWD by sending power to all the wheels. It has a different transfer case setup than any other F-Series (except Raptor). Same holds true with 4H and 4L, if you need them, switch to them.
If that's the case, then Ford needs to do a much better job of describing the functionality, especially if the Limited has a unique drivetrain.

And it's important to distinguish the difference between applying torque "to the front axle as a whole" and applying torque "to individual wheels".

Intelligent AWD in my opinion would include applying torque to individual wheels (front and rear) as needed and as traction conditions allow / indicate. If the Limited is the only trim level that has this feature, it'd be of great benefit to me.
 

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- When Platinum is in 4A, the truck will operate in RWD/2WD until the computer recognizes a condition where it needs more traction or conditions warrant the truck sending power to the front wheels. If you are in a condition where you need 4WD, switch to 4H or 4L on the dial, as 4A is not meant to be used off-road.

Lariat / KR / Platinum

Ford F-150 Limited AWD vs Platinum 4WD Drivetrain 1603729466841

Ford F-150 Limited AWD vs Platinum 4WD Drivetrain 1603729496218

Ford F-150 Limited AWD vs Platinum 4WD Drivetrain 1603729520553

Ford F-150 Limited AWD vs Platinum 4WD Drivetrain 1603729554335


Limited

In 2021's the only difference is the last line in the 4Low post above...all others are the same...
 
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- When Platinum is in 4A, the truck will operate in RWD/2WD until the computer recognizes a condition where it needs more traction or conditions warrant the truck sending power to the front wheels. If you are in a condition where you need 4WD, switch to 4H or 4L on the dial, as 4A is not meant to be used off-road.

Lariat / KR / Platinum

1603729466841.png

1603729496218.png

1603729520553.png

1603729554335.png


Limited

In 2021's the only difference is the last line in the 4Low post above...all others are the same...
Thanks for the info Granger! At the top of the post you include the trim levels "Lariat / KR / Platinum", can I assume that the 4A feature also applies to the Limited?

And the one feature listed that is specific to the Limited (new for 2021), "Includes mechanical locking 4WD", what does this mean? How is that feature beneficial and when would you want to use it?
 

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And the one feature listed that is specific to the Limited (new for 2021), "Includes mechanical locking 4WD", what does this mean? How is that feature beneficial and when would you want to use it?
I think what this means is the Limited's Transfer Case actually has some sort of clutch style differential in it so it truly operates as AWD with sending anywhere from 0% to 50% of the available torque to the front wheels in 4A. Because this Transfer Case has a differential to apportion the torque, it also needs to have a differential lock so you can manually lock it into true 4wd so that it always sends 50% front and 50% rear.

As for when you'd want to lock the center diff, anytime you are actually off the paved roads and want a true 4x4. AWD is great for on-road inclement weather, 4wd is generally better off-road than AWD, but that is more the case when you are in real off-road situations.

I would take it that the Lariat, KR, & Platinum do not have the capability of varying the torque to the front wheels from anywhere between 0% - 50%. Whatever clutch pack or actuating system is in the Transfer Case for these trucks acts more like an on/off switch, either sending 50% to the front wheels, or 100% to the rear wheels when in 4A.

But these are just guesses. The best source of information would be to look up the specific Borg Warner Transfer Cases on the internet and see what BW says about their modes of operation.
 
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05RubiconLJ

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If that's the case, then Ford needs to do a much better job of describing the functionality, especially if the Limited has a unique drivetrain.

And it's important to distinguish the difference between applying torque "to the front axle as a whole" and applying torque "to individual wheels".

Intelligent AWD in my opinion would include applying torque to individual wheels (front and rear) as needed and as traction conditions allow / indicate. If the Limited is the only trim level that has this feature, it'd be of great benefit to me.
I did some reading on this. I did not find information that was specific the specs of the 2021, but this is what Ford offered in the previous generation.

- 4A in previous years was only available in the Platinum, Limited, and Raptor trim.
- 4A allows the front and rear driveshaft to spin at different speeds and power is only sent to the front wheels if slip is detected.
- Shifting into 4H/4L locks the driveshafts together so that they turn at the same speed.
  • 2-High – standard rear-wheel drive
  • 4-Auto – all-wheel drive in which power is sent to the front wheels when slip is detected
  • 4-High – all four wheels are engaged in 4WD
  • 4-Low – a 4WD crawl mode where all four wheels are engaged.
I think this BW video explains it best.
 
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I did some reading on this. I did not find information that was specific the specs of the 2021, but this is what Ford offered in the previous generation.

- 4A in previous years was only available in the Platinum, Limited, and Raptor trim.
- 4A allows the front and rear driveshaft to spin at different speeds and power is only sent to the front wheels if slip is detected.
- Shifting into 4H/4L locks the driveshafts together so that they turn at the same speed.
  • 2-High – standard rear-wheel drive
  • 4-Auto – all-wheel drive in which power is sent to the front wheels when slip is detected
  • 4-High – all four wheels are engaged in 4WD
  • 4-Low – a 4WD crawl mode where all four wheels are engaged.
I think this BW video explains it best.
Very helpful, thanks.

So I guess it comes down to what "4A" actually means for the various trim levels, if in fact there are actual differences.

One possibility is that on lower trim levels, e.g. (Lariat/Platinum), 4A will automatically and seamlessly apply 50% of the power to the front axle and 50% to the rear... A 4WD "on/off" approach that is "hands off" once in 4A mode.

If the above is true, then the 4A implementation on the Limited could be automatically and seamlessly applying a varying degree of power to front axle, anywhere from 0-50% (with the balance of power remaining in the rear).

Either way, it would appear that there's no feature in the F150 lineup that would apply power to specific wheels, only to specific axles.
 

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This is the image that had me concerned. I think its an older one and probably computer generated. Notice no 4A in lower left quadrant of switch.
2F28BC63-C030-4224-BC44-5DF7A795F8F3.jpeg
It is computer generated and most of the interior pics like that don’t show 4A. The TOD transfer case (4A) is available on lariat and up. XL and XLT and Lariat with the snowplow package have the Electric Shift On The Fly transfer case.
 

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I'm trying to decide between a similarly equipped 2021 Limited vs Platinum, and which drivetrain would be best suited for my use and needs. Limited has the AWD (only option), and the Platinum would have 4WD.

For reference, my current vehicle is a 2010 Lariat 4x4, and I live in southeast Michigan. We have snow ~4 months out of the year. It's typically not deep snow, but during winter it would be slick with only a 2WD pickup. Even though we have a 4-month winter, the overwhelming vast majority of that time roads are not snow covered. Within a relatively short time after a big snowfall they're plowed and salted, so for the most part just wet and slushy.

I currently engage the 4x4 on my Lariat when the roads are snow covered. What I've noticed in 4x4 mode in snow is that when turning tight radiuses in parking lots, the wheels tend to "chatter". I've comed to learn this it's due to each wheel turning with the same rotational force, and when turning the inside wheels require less rotation / travel compared to the outside wheels, yet the 4x4 forces the same rotation/travel regardless. (If my understanding / description of this is incorrect, please let me know).

There are a few times up north in the winter where I'm driving on roads through snow that is deep (5"-10") and/or consistently tracked/rutted for longer periods of time, and in those cases I'm in full 4x4 mode. The only other use case where 4x4 comes in handy is when pulling my boat out of the water on a cement ramp that is slick.

So considering that I never take my F150 to go "offroading", which drivetrain do you think would best suit my needs? AWD or 4WD? And on the Limited AWD, is it seamless and automatic AWD?
The AWD system is the same on Lariat and above.
More than likely that’s just a misprint because the real B&P for the 2021 F150 hasn’t been released.
 
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As a related follow-up question on this topic, when pricing out a 4x4 Limited, you are given the following options for Rear Axle Ratios:
  • 3.31 Electronic Locking Axle Ratio $420
  • 3.31 Non-Limited Slip Axle Ratio Included
  • 3.55 Electronic Locking Axle Ratio $470
  • 3.73 Electronic Locking Axle Ratio $570
I understand the pros and cons of going with a taller axle ratio, but what are the pros / cons between the standard "Non-Limited Slip" and "Electronic Locking" options?
 

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As a related follow-up question on this topic, when pricing out a 4x4 Limited, you are given the following options for Rear Axle Ratios:
  • 3.31 Electronic Locking Axle Ratio $420
  • 3.31 Non-Limited Slip Axle Ratio Included
  • 3.55 Electronic Locking Axle Ratio $470
  • 3.73 Electronic Locking Axle Ratio $570
I understand the pros and cons of going with a taller axle ratio, but what are the pros / cons between the standard "Non-Limited Slip" and "Electronic Locking" options?
Electronic locking is ideal to have both rear wheels locked to go in a straight line like pulling. Boat out of the water or in deep snow= mud
 

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I understand the pros and cons of going with a taller axle ratio, but what are the pros / cons between the standard "Non-Limited Slip" and "Electronic Locking" options?
I live in a pretty sandy area and my k1500 has locking differentials.
When my 4x4 developed an electrical issue, I found myself in the back yard next to a tree with no front wheel action.
Shift TC into 4Low and was able to trench my way to a bit more solid ground.
Both rear wheels were locked and digging equally—I’d have never got out out of there without my neighbor’s tractor.
The only issue with a “locker” is that on wet or slippery roads, particularly in a turn, both rears are turning the same. This is not in your best interest in a turn and the back of the truck will undoubtedly try to pass up the front.
Had 4x4 vehicles while growing up in Idaho, and actually despised driving the trucks on icey roads for a couple of reasons.
When in 4x4 the truck really had no idea where it wanted to go
When in 2hi, there was not enough “weight transfer” to get the rears to “bite” either for braking or pulling away.
Always preferred my Chrysler’s for ice (sticky soft tires, soft springs, weight transfer)
Snow or slushy roads, the pickups every time
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