How does AUTO 4WD work/what does it do?

[CostaRam]

IMO auto 4x4 settings are for the Soccer Mom Mobiles and not a truck.

i 1000% agree and would add some other type of persons, but to be political correct i don't name them ...

 

[Jared4.7]

So maybe I'm missing something but if 4x4 "lock" isn't engaged all the time what is the difference between auto and lock? It's been said that in auto the transfer case is engaged but the clutch packs aren't engaged. So...what's the difference?

All buttons that do pretty much the same thing. But, absolutely no true "lock" at all in the auto t-case UNTIL it senses wheel slip at the rear. Everything up front can be engaged but it receives no power until the truck senses wheel slip and the clutches in the case lock.

 

[mohemipar]

As far as I understood what I have read, in auto you only get additional wheels powered for the time it takes to correct the loss of traction. Then it will instantly revert back to standard RWD. In lock mode itll keep the other wheels powered after first loss of traction and then turn off after a certain parameter is met, but I don't know exactly what those parameters are because there is mixed info out there. Mine seemed like it held until I let off the gas from what I remember.

 

[Reddington]

So I have been driving around WNY for a couple of days now in the snow and to me the system is working just fine. I have not had any issues with it and I have been out in some pretty crappy roads the last few days.

 

[pickupman66]

**** NOTE. this does not apply to select 2009 model 1500's that have the NVG-246 transfer case with the Auto function. when in Auto, it will only engage the front prop shaft when wheel slip is sensed. BUT in LOCK, it does not use clutches and is indeed locked.

 

[muddy12]

There is a video floating around someplace (will see if I can find it tomorrow when I have access to a computer) that describes how the 44-44 case works. But, in a nut shell, there is an electromagnetic actuator, and a clutch pack inside the case.

The electromagnetic part controls weather or not power is sent to the clutch pack. The clutch pack uses input torque to close the clutches and send power to the front.

So, in 2wd, electronic part is off, and no power is sent to the clutch pack.

In 4auto, the computer controls the electromagnetic part based on wheel spin/loss of traction.

In 4lock (and 4lo) the electromagnetic part is constantly on. This means that drive power is constantly being sent to the clutch pack.
However( and it’s a big however) because of how the clutch pack engages, a noticeable amount of wheel spin is needed before power is sent to the front wheels.

Sorry for the poor explanation, I’ll find that video tomorrow.


Sent from my iPhone using Tapatalk

 

[Joes1500]

I would appreciate seeing this video if you can find it.

 

[Jeepwalker]

This is very interesting. I wonder why they did it this way? The simple approach would be to maintain things as they had always been with old-school xfer cases, or a viscious clutch. Obviously there was some triggering reason they went out of their way and spent a fair amt of money to come up with this design. What do you think some reasons might be why they designed it to perform the way they did? I wonder if it is to preserve the mechanics because a good number of owners didn't understand how to use the old 4x4 system and wore them out on dry pavement? Maybe it was simply fuel economy?

How does it perform in deep snow, on the road under variable conditions like going up hills, around corners, leaving stop signs and so on? Normally in these kind of conditions is where the old-school 4wd Lock would come in super handy. It would send power to front/rear wheels together.

 

[muddy12]

How does it perform in deep snow, on the road under variable conditions like going up hills, around corners, leaving stop signs and so on? Normally in these kind of conditions is where the old-school 4wd Lock would come in super handy. It would send power to front/rear wheels together.

Not sure about deep snow, think I maybe used 4x4 one time last winter.
This spring, however, I is trying to back a trailer load of building materials into position in my yard.
The yard is slopes pretty good, and in an attempt to prevent the truck from sliding around, I put it in 4lo. Even in 4lo, the rear tires still broke loose a few times. Each time the tires slipped, it took just about 1 full revolution of the rear tires before the fronts engaged.

 

[BWL]

This is very interesting. I wonder why they did it this way? The simple approach would be to maintain things as they had always been with old-school xfer cases, or a viscious clutch. Obviously there was some triggering reason they went out of their way and spent a fair amt of money to come up with this design. What do you think some reasons might be why they designed it to perform the way they did? I wonder if it is to preserve the mechanics because a good number of owners didn't understand how to use the old 4x4 system and wore them out on dry pavement? Maybe it was simply fuel economy?

How does it perform in deep snow, on the road under variable conditions like going up hills, around corners, leaving stop signs and so on? Normally in these kind of conditions is where the old-school 4wd Lock would come in super handy. It would send power to front/rear wheels together.

Getting going from a stop in deep snow, ice and mud on a hill, which basically is when you need 4wd the most it's not so good. Trying to slowly get going when you lack traction doesn't always engage the 4wd and if you have the TCS on it only makes matters worse because once you do get moving it throttles down so much you get stuck again because you lose momentum. TCS off quickly seems to overheat the clutches and then 4wd won't work until they cool down. It's not a 4wd system for people that truly require 4wd. That's why I insist on limited slip and carry chains and tow straps in my truck. I need them more than I used to with my older trucks that had actual 4wd

 

[Jeepwalker]

Are Ford and Chevy doing the same thing? How can they claim to have a superior 4x4 system? Seems like a step backwards in real-world usability ....if I'm hearing you guys right.

 

[BWL]

Are Ford and Chevy doing the same thing? How can they claim to have a superior 4x4 system? Seems like a step backwards in real-world usability ....if I'm hearing you guys right.

They're much the same. The ford has the electric locking rear diff option which helps since it gets both rears spinning easier than the limited slip, but the transfer case system is pretty similar as far as I know.

 

[BWL]

I know in the HD ford has a proper t case with manual locking hub option. They're kind a a pain since you have to get out to lock up the front hubs, but it does keep the front diff disengaged rolling down the road and the 4wd works really well when locked in. Pretty sure GM and dodge HD trucks have proper 4wd as well.

 

[Machria]

Great info, thanks guys. Sorry to say, nowadays I'm that "average joe" guy that this will work perfectly fine for. Occasional snow storm, a mile or 2 offroad now and them, and a couple ski trips up to VT is all I really need the 4wd for. I used to be in deep soft sand often when driving down the beach to go surfing, but I'm getting to old for that!!

Thanks for the description....

 

[Machria]

Definitely post the video if you find it, I'd also love to see it....

 

[Joes1500]

I found this video on YouTube. Looks like it operates fine. But I could see the heat and clutch issue becoming a problem under some severe use.

Watch "4WD TEST : 2016 Ram Truck Laramie Limited Ecodiesel Diagonal and Offroad test on ice and snow" on YouTube

 

[Machria]

Yep, I watched this video prior to buying mine..... worked fine for what I need it for. It's not a lifted HD with 3500 size springs on it, but it does get up the snowy hill!

 

[Jeepwalker]

Well, the video doesn't show it going down back roads, around turns, curves and hills with 4-5" of snow on the road and oncoming traffic ....or slushy areas that want to pull ya off the road or across the center lane if you don't have good stability. THAT's where good 4x4 becomes critical. An older jeep with 'full time' (not always locked) was good, but not nearly as good as having it in 'full time' (center locked) when you got on the really slippery stuff. Sometimes a second or two for the 4x4 to kick in is the difference between the ditch or not. I guess I'll keep an open mine because I haven't driven one.

 

[BWL]

Well, the video doesn't show it going down back roads, around turns, curves and hills with 4-5" of snow on the road and oncoming traffic ....or slushy areas that want to pull ya off the road or across the center lane if you don't have good stability. THAT's where good 4x4 becomes

critical. An older jeep with 'full time' (not always locked) was good, but not nearly as good as having it in 'full time' (center locked) when you got on the really slippery stuff. Sometimes a second or two for the 4x4 to kick in is the difference between the ditch or not. I guess I'll keep an open mine because I haven't driven one.

At speed in icy conditions the 4wd and traction control work pretty good to keep you out of trouble. It's really just not that Good at getting you going in the first place.

 

[Cardhu]

The part time system in the jeeps is what i was expecting when i pushed lock. While it is more useful / aggressive than auto, locked it isn't.

When in 4Lo its pretty annoying when you want to crawl over something, it just makes you hit it harder than you should or keep your foot as subtle on the gas as possible to keep it engaged. In one of the many i hate the BW44-44 threads, somebody reported part of the circuit is energized when lock is selected and will turn the front wheels faster. I would tend to agree that it works better than auto when your actually using it.

Why FCA assumed that high end rams needed a transfer case that was so "user" friendly is still mind blowing. you'd think transfer cases have fallen out on the pavement of every second truck for the last 20 years. Then again the more people i hear of using 4WD in the rain, they may have a point.