Confused about 4WD and eSLD

[ExpyG]

Hi all,

I am coming from the Honda/Acura background. Last summer I rented an Expedition MAX for a road trip and loved it so much that I decided to buy one. So after waiting a few months, I am finally in the market for a new Expedition MAX, my first Ford vehicle

I am in the Northeast. All the Expys sold around here have four wheel drive, and I would not buy one without it even if they were available, because of all he snow and ice we get.

I am confused in that some Expy's (even with 4WD) list eSLD on the window sticker and some don't. When one wheel a non-limited-slip-differential vehicle gets on a patch of ice, wouldn't that wheel just spin? And the other wheel on the same axle would receive no power? Then how is it a 4WD vehicle? On my Acura MDX every wheel receives as much power as it needs at any given time. So I just drive normally and if one or more wheels get on a patch of ice, the car stops sending power to the wheels that slip. If I accelerate through a turn, the car sends more power to the outside wheels. Is this what the 4A mode does on the Expy? How can a non-limited slip differential work in 4A?

Sorry about all the questions. It is just all so different from what I am used to. But I love the Expy and can't wait to make the switch.

 

[Soliyou]

For a non-limited slip (open diff), yes, one wheel would spin on ice and the other will do nothing. However, the traction control will apply the brakes on the spinning wheel and sends torque to the other to get you out.

The 4A refers to the transfer case that can modulate the power between front and rear axle via a wet clutch pack. This prevents binding on paved surfaces.

This system cannot overdrive a single wheel like the Acura’s

But with eLSD and clutched transfer case, the expy is phenomenal on snow. I only wish they have a locker on the front diff.

 

[Calidad]

ESLD vs just basic 4H is just more complex technology in the axle. Your Honda is a clutch / friction driven system paired with the ABS the simplest way to think of it is the car uses the brakes at each wheel to prevent excessive wheel spin. That spinning wheel gets braked and when that occurs the power gets pushed across the drive system to the opposite wheel.

The more complex the system is at not just limiting wheel spin and shifting power through the drive system the more complex the traction logic can be. The higher the trim package the more technology you typically can get.

For example the XLT with no trailering package simply has 2wd and 4wd and basic modes Snow -dirt etc. In this configuration it doesn’t have the costly clutch system and the modes primarily just alter throttle sensitivity, power reduction due to wheel spin sensitivity and likely some steering rack sensitivity.

The higher trim models get the more expensive clutch based system which gives more control to the modes and 4wd settings in how much power goes where when etc. Like your Acura but with far more logic in the various modes.

Yes the Expeditions use braking force to limit spin or push power across open diff to opposing wheels. The braking system is the most basic and rudimentary aspect of these systems. But with esld technology it can be paired up with pretty impressive logic to work in conjunction with the power system and be quiet good at finding traction when little traction is to be found.

 

[Gumby]

My platinum has 4A only. That combined with the various drive modes works perfectly. In the snow, in 4A with SNOW mode is fantastic....and we get lots of snow (deep) and ice along with -40C temps. When paired with dedicated winter tires, you are good to go.

 

[Expedition Dave]

2wd is standard and AWD (often called "4wd") an option.

To get proper 2WD, 4hi, 4low and terrain management (and maybe the e-Locker) I believe you have to go with either the FX4 package and/or the Heavy Duty towing.
I have both, so have all.

Like the Chevy, if you want 4 low it needs to be part of the option box check as it is not standard with "4wd" (AWD) any more.

 

[ExpyG]

Thank you all so much! If I am not planning on any towing, but only concerned with ice/snow and handling, should look for a vehicle with eLSD or is the XLT 4x4 enough?

 

[Calidad]

ESLD vs just basic 4H is just more complex technology in the axle. Your Honda is a clutch / friction driven system paired with the ABS the simplest way to think of it is the car uses the brakes at each wheel to prevent excessive wheel spin. That spinning wheel gets braked and when that occurs the power gets pushed across the drive system to the opposite wheel.

The more complex the system is at not just limiting wheel spin and shifting power through the drive system the more complex the traction logic can be. The higher the trim package the more technology you typically can get.

For example the XLT with no trailering package simply has 2wd and 4wd and basic modes Snow -dirt etc. In this configuration it doesn’t have the costly clutch system and the modes primarily just alter throttle sensitivity, power reduction due to wheel spin sensitivity and likely some steering rack sensitivity.

The higher trim models get the more expensive clutch based system which gives more control to the modes and 4wd settings in how much power goes where when etc. Like your Acura but with far more logic in the various modes.

Thank you all so much! If I am not planning on any towing, but only concerned with ice/snow and handling, should look for a vehicle with eLSD or is the XLT 4x4 enough?

4x4 or 4A is plenty it’s basically the sane as your Acura though I do believe Ford has given it far more logic than the hands off basic FWD biased Acura system. If anything you’ll likely find it better than the Acura.

 

[Soliyou]

The Acura system is actually a very advanced system since it is capable of sending more power to the rear axle and put all the power only on one wheel! You really get some rear wheel drive dynamic with this system. In sticky off-road situations, you just maintain steady gas pedal pressure and it will figure it out for you.

I would vote for eLSD if within your price range.

 

[grumpyoleman]

I have had my XLT with 4A only for two Dakota winters now and no regrets. I don't do any off roading (nothing serious anyway) but it gets me to work without any serious drama no matter how much white stuff is being blown around...

 

[Calidad]

The Acura system is actually a very advanced system since it is capable of sending more power to the rear axle and put all the power only on one wheel! You really get some rear wheel drive dynamic with this system. In sticky off-road situations, you just maintain steady gas pedal pressure and it will figure it out for you.

I would vote for eLSD if within your price range.

You do realize this is industry standard with all modern platforms right? Well except for Toyota they are still lagging.

Brake vectoring technology is very simple and cheap to have on all modern ABS vehicles. The Acura is not special today its simply just average

 

[lv2drive]

being raised up on audis, i would venture to say that the expy w good shoes has by far exceeded my expectations on snow/ice/mix. i prefer the precision articulation of the quattro & how it does not use braking to control wheel spin - and hell yea if audi made an expy sized beast & i could afford the mortgage for it then maybe there could be a comparison - but the expy 4wd drive control system, combined with the sheer weight & power just dominates any subtle precision control i’m missing from the quattro. to add, ive got the non-elsd 4wd.

i’ll put it this way - when the snow was crushing us this season, not once did i take out our diesel touareg (haldex audi drive & incredible in the snow). left it at home & took the expy. every. single. time.

 

[Soliyou]

You do realize this is industry standard with all modern platforms right? Well except for Toyota they are still lagging.

Brake vectoring technology is very simple and cheap to have on all modern ABS vehicles. The Acura is not special today its simply just average

The Acura system is not brake torque vectoring. It is a real torque vectoring system.

They use clutches and gears in the differential to direct the power, up to 100% to one rear wheel.

https://www.motortrend.com/news/what-is-sh-awd-acura-torque-vectoring-system/

 

[Armin]

Based on your link it is "just" a limited-slip differential. It can move up to 70% of the power from the rear back to the read left and reverse.

I say "just" as you are absolutely correct that is not standard on most cars and not just brake torque. But it is also hardly new. My 1990 Porsche already had that, although I'm sure the Acura will transfer the power much smoother and quicker (more proactive I assume as well) than that old thing did. But even Porsche called it 4-wheel steering, so the concept and marketing were alike already

In essence this sounds like the eLSD option the Expedition has. So the OP/ExpG should get either the FX4 or HD-tow as that has eLSD option. On top of the Acura system you will then also get the simulated manual lock of the eLSD, 4H though snow/ruts mode and 2L through the transfer case. So the OP/ExpG should have no issues in snow. The accent is probably different. The Acura will be more about performance and cornering and the eLSD software more about keeping it straight with towing and not slipping when crawling.

 

[ShannonD]

So my 2 cents to answer your question. In my humble opinion, unless your planning to do off-road or heavy towing, I personally think you'll be great with the XLT and up 4x4 system. If your planning to do off-road, get the FX4 package. We had the worst winter we've had in 30 years here in Oklahoma this year. I'll say I was very impressed with my 2020 XLT 4x4 in 4a and all the drive modes. It did way better than my 18 Silverado 4x4 with locking diff etc.

 

[AmpForE]

Thank you all so much! If I am not planning on any towing, but only concerned with ice/snow and handling, should look for a vehicle with eLSD or is the XLT 4x4 enough?

Yes,

A vehicle with eLSD will perform better than one without. The eLSD sends torque to the wheel with the most grip without using the brake, which slows the SUV. This will be a step above your Acura. Good Luck.

 

[AmpForE]

So my 2 cents to answer your question. In my humble opinion, unless your planning to do off-road or heavy towing, I personally think you'll be great with the XLT and up 4x4 system. If your planning to do off-road, get the FX4 package. We had the worst winter we've had in 30 years here in Oklahoma this year. I'll say I was very impressed with my 2020 XLT 4x4 in 4a and all the drive modes. It did way better than my 18 Silverado 4x4 with locking diff etc.

If you had an eLSD model, you would have been more impressed.

1st, eLSD’s are ALWAYS working, not just in snow and off road. Driving on the highway and need to make a quick lane change, the eLSD works to make it smoother. In rain, you are stopped and turning, the eLSD reacts. Vehicle handing is improved, it’s why all racing road and dirt use an eLSD. Go to YouTube and watch the video.

There’s no condition where an open diff using brakes to control torque will be better or just as good as on with an eLSD. It may be good enough for you, but not equal in any use case other than driving in a straight line. Lol