A Friendly Reminder on Drive Modes for 4WD

[Expedition Dave]

A Friendly Reminder on Drive Modes for FX4 4WD/Etc.

TLDW: Mud/Ruts is 4WD where the front and rear are 'locked' via the center differential clutches with no Traction Control. Sand mode is the same, but with traction control.
It would stand to reason (IWSTR), that this mode--with the E-Locker, would be the best way to prevent the dreaded "4x4 Temporarily Disabled" due to center and rear clutches overheating.

https://www.youtube.com/watch?v=-cyvS0iC7BY

 

[LokiWolf]

There is no front locker on the Expedition. It is an open Diff. Pretty sure you meant center and rear and not F&R in your first sentence.

The Expedition uses NO pin locks, and is all clutch based both in the Center and Rear. The Expedition DOES NOT have an E-Locker, it has an ELSD(Electronic Limited Slip Differential) with a "simulated" locker. The way it "locks" is to provide constant pressure to the clutches. Under certain conditions they will overheat, and disable.

The F150 has a rear E-Locker, no LSD, just a pin lock. The Raptor center diff can pin lock, and maybe the Tremor too if I remember correctly.

Owning both, other than true off road conditions, the ELSD is the superior setup. It just works!

 

[KSC 2019 XLT]

I have a 2019 Expy XLT 4WD (not the FX4 and no tow package). Recommendations on what drive mode to use when going up and down the snowy mountains when skiing? I think the mud/rut mode as the owners manual says all four wheels are powered at all times. I think you are not supposed to go fast in this mode but I won't be anyways. I've gone skiing using 4A in Normal driving mode and on one trip the tail spun around going down a slight decline. Scared the hell out of me as one side was a drop off down the mountain. Luckily the Expy didn't spun all the way around and corrected out of it.

 

[kjtully]

I have a 2019 Expy XLT 4WD (not the FX4 and no tow package). Recommendations on what drive mode to use when going up and down the snowy mountains when skiing? I think the mud/rut mode as the owners manual says all four wheels are powered at all times. I think you are not supposed to go fast in this mode but I won't be anyways. I've gone skiing using 4A in Normal driving mode and on one trip the tail spun around going down a slight decline. Scared the hell out of me as one side was a drop off down the mountain. Luckily the Expy didn't spun all the way around and corrected out of it.

Living here in Colorado I use 4H when there is enough slick stuff (rain, snow, or ice) on the road - or potential to encounter slick stuff - city or highway driving. I'll change to 4A when in a parking lot and making frequent hard turns. To me the point to change from 4H to 4A is when there is the potential of diff binding and tire skip when making turns. On trips in the mountains where snow is at the higher elevations and dry at the lower elevations I'll switch between them - if traffic is slow I'll switch or pull over to make the switch. While not often, I've done 75 - 80 in 4H until I get (or take) the opportunity to change to 4A or 2H. Some trips I have switched to 4H just before heading up into the mountains knowing that somewhere along the way I will encounter snow on the highway.

Now driving MODE is a different story. My old 2003 Expy didn't have the fancy driving modes so I didn't have to think about it. Personally I'll most likely stay in Normal or Eco driving in snow. I might try the mud/rut mode in thick deep snow (probably in combo with 4L), but otherwise Normal/Eco should be sufficient driving Colorado winter roads.

I think it all comes down to what combination of things you feel most safe using and feel are appropriate for the conditions to get you where you're going safely.

 

[shane_th_ee]

Coming to my Expedition from an XJ Cherokee (with mechanical 2H/4H/4L and no traction control) for “normal” snow and normal grades, I think you want to use snow mode. The reason you don’t want to use 4H (or mud/rut) is that having the front and rear locked together means that torque steer on the two axles wants to spin the vehicle, because the forces are in opposite directions for each axle. This is usually what causes various four wheel drive vehicles to end up in the ditch pointing the wrong way coming back from skiing. Tap the accelerator just as you hit a patch of black ice, ‘round you go!

On an old school 4x4 like my jeep, the solution is to use 4H to get started and then switch into 2H until you have to start again.

Snow mode will work with the traction and stability control systems and attempt to do all sorts of things to keep that from happening.

That said, if it’s really steep and really slippery, you want to engage 4L before you start the descent, lock out all the gears but 1, and let the engine do all the braking.

 

[LazSlate]

Coming to my Expedition from an XJ Cherokee (with mechanical 2H/4H/4L and no traction control) for “normal” snow and normal grades, I think you want to use snow mode. The reason you don’t want to use 4H (or mud/rut) is that having the front and rear locked together means that torque steer on the two axles wants to spin the vehicle, because the forces are in opposite directions for each axle. This is usually what causes various four wheel drive vehicles to end up in the ditch pointing the wrong way coming back from skiing. Tap the accelerator just as you hit a patch of black ice, ‘round you go!

On an old school 4x4 like my jeep, the solution is to use 4H to get started and then switch into 2H until you have to start again.

Snow mode will work with the traction and stability control systems and attempt to do all sorts of things to keep that from happening.

That said, if it’s really steep and really slippery, you want to engage 4L before you start the descent, lock out all the gears but 1, and let the engine do all the braking.

I agree. I think the Modes Ford came up with should be used first. They test in all conditions and they know how the traction control, locking and mechanics work. Some modes they disable traction control and stability type controls. Like Sand is a special beast to drive in. I have had my share of plenty of deep sand and IMO you want them locked and all 4 driving with no stability or traction control. I have not looked but would assume Ford has done this in Sand mode. I plan to always use the Ford Modes and manually adjust to conditions as they change.

 

[shane_th_ee]

I agree. I think the Modes Ford came up with should be used first. They test in all conditions and they know how the traction control, locking and mechanics work. Some modes they disable traction control and stability type controls. Like Sand is a special beast to drive in. I have had my share of plenty of deep sand and IMO you want them locked and all 4 driving with no stability or traction control. I have not looked but would assume Ford has done this in Sand mode. I plan to always use the Ford Modes and manually adjust to conditions as they change.

I have also tested sand mode. It works well!

 

[KSC 2019 XLT]

Coming to my Expedition from an XJ Cherokee (with mechanical 2H/4H/4L and no traction control) for “normal” snow and normal grades, I think you want to use snow mode. The reason you don’t want to use 4H (or mud/rut) is that having the front and rear locked together means that torque steer on the two axles wants to spin the vehicle, because the forces are in opposite directions for each axle. This is usually what causes various four wheel drive vehicles to end up in the ditch pointing the wrong way coming back from skiing. Tap the accelerator just as you hit a patch of black ice, ‘round you go!

On an old school 4x4 like my jeep, the solution is to use 4H to get started and then switch into 2H until you have to start again.

Snow mode will work with the traction and stability control systems and attempt to do all sorts of things to keep that from happening.

That said, if it’s really steep and really slippery, you want to engage 4L before you start the descent, lock out all the gears but 1, and let the engine do all the braking.

My 2019 Expy 4WD doesn't have 4L unfortunately. It's either 4A or 4H (via Mud/Rut mode).

 

[sjwhiteley]

My 2019 Expy 4WD doesn't have 4L unfortunately. It's either 4A or 4H (via Mud/Rut mode).

If it’s slick, use 4A. As conditions worsen, use what is says on the box. I’ve used the snow and grass modes, and they work very well. Remember that the tires you have can have a significant impact on the effectiveness of the mode you are in.

I didn’t think the non-FX4 non-HD had 4H (can’t recall what versions have it, I only have 4A). In snow mode, it looks like all 4 wheels drive in 4A.

 

[Expedition Dave]

Yup Loki, I used a **** ton of bad wordings in my OP on things I already knew--so thanks--I fixed it.
Did not know the center was eseentially the same as the ELSD in the rear and wonder if the center will slip enough to overheat the system as well?

I would like the option of real pin locks ro at least a system that did not overheat.