4WD auto?

[Fatherof3]

Very interesting. Are the Goodyear's decent?

I have the Goodyears on my Rebel and I've only used 4WD maybe 3-4 times in the 2 years I've had my truck . I'm in Ontario Canada so you know I deal with snow .

 

[LouNY]

Dang what a thread,
some good advise and some not so good.
Back to the OP when 4w auto is activated the front axle internal disconnect is
activated and the axle is ready for the transfer case to send power to it.
When turning sharply the front axle u-joints are being rotated when they are at their extreme articulation.
A u-joint can and will give a pulsating feel in a driveline at those times.
To isolate the issue with "binding" simply remove the front driveshaft and try your tight turns again,
any binding or jumping at that time will be in the front axle and it will not matter what mode
the transfer case is in.

As far as the differences in the t-cases with and without the auto function,
I need both the auto is nice in the summer, I don't like it in the winter.
My previous 2015 sucked with the auto pure and simple after I installed "Brandons" switch kit it was much better.
We will have to see how well the 2019 does, I sure hope it is better.
Much of the problems with the 2015 was RAM's programing and the operational
characteristics of an electric clutch to activate 4wd,
a good electrical hydraulic 4wd clutch would activate to disengage and loss of power
results in full engagement.

 

[Redfour5]

So I don’t know anything about 4WD. It started raining pretty bad here. With that said, there was wheel spin when I took off at the light. I didn’t punch it and it was on 2WD mode. When it’s heavy rain, am I suppose to put it on 4WD auto? What’s the high and low for? I believe low is when you have lots of weight and you need to get up at a slow speed.

Auto is kind of like having a second rate AWD like most AWD cars have without having true 4WD. The difference is that 4WD is engaged if slip occurs vs a true AWD system. If it senses slip it sends power to the front axle 4WD. If it senses slip and you have a rear LSD, I am not sure of the sequencing for it to kick in. To a degree it "might" compensate a bit if you do NOT have a rear LSD but instead have an e-locker (off road package). It kicks on when you have the spin effect you noted. There are a million threads and posts on this in other forums. Some say, since you are activating system that does NOT have to be on, there is a reason for that button. The implication is that it should NOT be on all the time. Reasons explained include wear and tear, lessened mileage, blah blah blah. People have left it on for the entire life of their vehicles with no problems. A light tells you it is on. So, in all this time, I have never seen any explanation from RAM other than what is in the manual. It doesn't address having it on all the time but if you twist your head, there is an implication that it is not expected for it to be on all the time, simply because it is there as a choice. Engineers on some threads have explained that it uses a different borg warner transfer case (44-40) that has clutch packs as does the anti-spin rear differential. I don't know.

My first 2013 Quad cab did NOT have LSD and was basic 4WD. I have a bank of mailboxes we all stop at in the neighborhood fully polishing the snow in front of them. The 2013 forced you to put it in 4WD to get the truck to move and often after sliding to an area where you could get traction of some sort. Then my 2015 had a rear end limited slip differential and that solved my mailbox problem completely. I could feel the LSD grabbing traction. I remember going, OH, that's how it works. So, now I have the elocker on the off road package and I was a bit worried about going back to 2013 mailbox behaviors for the truck. I spoke to my local shop comprised of former Ram techs mostly still certified and who will tell you things the dealer won't. He said that you will still have a "form of" "similar to" (terms he used) LSD but it will be from back to front instead of side to side. There shouldn't be a problem and the elocker gives you a lot more capabilities than the regular 4WD. He's old school and not totally sold on elockers, but acknowledges they seem to do pretty well...overall. He works on Jeeps also. He likes LSD. On my 2015 when it quit on me while towing telling me to put it in park at 65 mph while throwing NO codes, he said it's likely in the ignition pathway... (The dealership didn't have a clue/but I'm on an extended warranty). He seems to know his stuff. He was explaining at a basic level to a non-mechanic/engineer. Here is one of those old threads that goes into it. Just google it. https://www.ramforum.com/threads/how-does-auto-4wd-work-what-does-it-do.112773/

So, for me in both rain and snow, I will push the button. Here in MT, I may push the button in the middle of September when we get our first foot of snow and not un push it until May. It always depends up here. Wet roads also. Mud, National Forest Roads generally I hit 4WD, but might start using the auto. I will have to play with it a bit. But in the summer when we go a month without rain, I'll put it in 2WD. It is a feature that is not really noted or mentioned by RAM. It also apparently has a light on when it is on. I don't like lights on except for tow haul and so that is another reason to not hit the button. I do not know if it automatically kicks off when you turn the truck off either like Tow/Haul. If it does, that is another tacit indication it is NOT supposed to be on all the time.

 

[Redfour5]

So I don’t know anything about 4WD. It started raining pretty bad here. With that said, there was wheel spin when I took off at the light. I didn’t punch it and it was on 2WD mode. When it’s heavy rain, am I suppose to put it on 4WD auto? What’s the high and low for? I believe low is when you have lots of weight and you need to get up at a slow speed.

This is a good article on it. https://4wheeldriveguide.com/when-to-use-4wd-auto-ram-1500-4a-guidelines/