Dumb question- 4 Auto

[vtcats]

Since I’ve owned my 2024 Limited for the last few months I’ve occasionally used 4H or 4 auto when the roads had snow on them. But most of the time, use 2 on dry pavement.
But this past weekend I had pulled over the side of the road a few times while looking for something and each time the tires spun out/slipped getting back on the road. Maybe a little gravel or loose dirt. But coming from an AWD (where that never happened) it was a pain as there were oncoming vehicles. Is there something that would break or functionally go bad if I used 4 auto all the time?
Other than “maybe” lower gas mileage?

 

[SpeedyV]

Auto 4WD is always “safe” to use. 4Hi should be reserved for known slippery conditions.

 

[Eighty]

The TRX doesn’t even have a 2wd mode. It’s 4-auto all the time (or 4-hi or 4-lo). So I’d say it’s safe to use

 

[Andymax]

Totally fine in AUTO mode. My truck did not come with locking rear diff so I often use 4WD Auto when I need to aggressively get going from a stop. I'm at 130K and no issues.

 

[cerbo]

Totally fine in AUTO mode. My truck did not come with locking rear diff so I often use 4WD Auto when I need to aggressively get going from a stop. I'm at 130K and no issues.

Good to know. I bought a 24 BTS and it has everything I wanted as far as options, except, I missed one detail, LSD or posi or whatever Ram calls it. It has locking rear switch but that s different. Like the OP er I noticed if the ground is wet or loose especially if pulling out in a turn that that one rear wheel just can t get the traction esp with the 5.7. With 2500 miles now I m hitting the 4 auto when in conditions I know it will help.
I can t believe that they all don t have LSD, it was my fault for not checking but I missed that.

 

[mikeru82]

You can't get both the locking and anti-spin rear diff, so you can't have both on the same truck. Just keep it in 4 auto and you'll be fine. Our 2020 Limited has been in 4 auto for most of the four years we've owned it.

 

[rick619]

You can't get both the locking and anti-spin rear diff, so you can't have both on the same truck. Just keep it in 4 auto and you'll be fine. Our 2020 Limited has been in 4 auto for most of the four years we've owned it.

Agree with this, it's one or the other. The rear locker is the more expensive option and better for off roading (if needed) and ice. Though as you may have noticed, it's not like a LS. LS is better for wet/gravel conditions. The locker is more extreme and shouldn't be used on dry pavement.

Jeeps are the same. Most have the LS, but a rear locker is an upgrade in some trim packages.

 

[cerbo]

Agree with this, it's one or the other. The rear locker is the more expensive option and better for off roading (if needed) and ice. Though as you may have noticed, it's not like a LS. LS is better for wet/gravel conditions. The locker is more extreme and shouldn't be used on dry pavement.

Jeeps are the same. Most have the LS, but a rear locker is an upgrade in some trim packages.

yea, the locker is pretty useless for me.

 

[mikeru82]

yea, the locker is pretty useless for me.

Shouldn't have bought a BTS then because the locking diff is part of that package. It's also part of the Off Road Group, which I had on a previous 5th gen. But using 4 auto solved any traction issues I had during winter driving. You'll be fine with that. You just need to be pro-active in selecting that before you need it.

 

[rick619]

yea, the locker is pretty useless for me.

You and most others will never 'need' a locker. I wanted it on mine, but really doubt I would ever use it. I'm not planning to do many black diamond trails in my DD.

 

[vtcats]

Thanks everyone. Sounds like I can just go to 4 Auto all the time. So I’m curios, what is my anti spin differential axle supposed to do anyway? Because it definitely SPINS while in 2WD

 

[mikeru82]

Thanks everyone. Sounds like I can just go to 4 Auto all the time. So I’m curios, what is my anti spin differential axle supposed to do anyway? Because it definitely SPINS while in 2WD

Are you sure you have anti-spin? Sounds like you just have an open diff...no e-locker and no anti-spin. It should be listed on your window sticker if you have it. Or you could check the build sheet to be sure.

Edit:
To get your window sticker, add your VIN to the end of this URL...
http://www.ramtrucks.com/hostd/windowsticker/getWindowStickerPdf.do?vin=

To get your build sheet, enter your VIN on this website...

FCA RAM

fcagroup.my.site.com

 

[vtcats]

I have it and that’s where I read it. Says exactly that word for word (anti spin differential rear axle $495). Also have 3.92 rear axle ratio

 

[mikeru82]

I have it and that’s where I read it. Says exactly that word for word (anti spin differential rear axle $495). Also have 3.92 rear axle ratio

When you get wheel spin when in 2 HI, is it both rear tires or does just one tire spin? If it's both tires your diff is working fine. You just need to learn how to put the power down without spinning the tires. If just one wheel spins there's something wrong with your diff.

Thanks everyone. Sounds like I can just go to 4 Auto all the time. So I’m curios, what is my anti spin differential axle supposed to do anyway? Because it definitely SPINS while in 2WD

The anti-spin diffs act as a limited slip differential. Some used to call it posi-traction back in the day. It's supposed to keep one wheel from spinning on its own, aka one wheel peel. One tire might spin a little before the diff reacts, but for anything more than a chirp both wheels should spin.

 

[rick619]

I have it and that’s where I read it. Says exactly that word for word (anti spin differential rear axle $495). Also have 3.92 rear axle ratio

I don't have it on mine. Though I did have it on my previous Jeep. It is really difficult to know it's there, not as effective as many of the aftermarket LS. For offroading, you could try to get it to activate if you needed it. You could put the parking brake on 2 clicks (not all the way on) and that would help it to activate. Though the Rams have the electronic parking brake, so can't really do that.

On the street, it's hard to tell the difference between having it and not.

 

[vtcats]

When you get wheel spin when in 2 HI, is it both rear tires or does just one tire spin? If it's both tires your diff is working fine. You just need to learn how to put the power down without spinning the tires. If just one wheel spins there's something wrong with your diff.


The anti-spin diffs act as a limited slip differential. Some used to call it posi-traction back in the day. It's supposed to keep one wheel from spinning on its own, aka one wheel peel. One tire might spin a little before the diff reacts, but for anything more than a chirp both wheels should spin.

Yeah, tough to tell but I kicked up some mud inside the wheel well, I’ll check the other as it should be on both sides. Either way, 4 Auto it doesn’t happen I assume.

 

[moosem]

I have anti-spin and they still spin. Lol. No weight in the back.

 

[mikeru82]

Yeah, tough to tell but I kicked up some mud inside the wheel well, I’ll check the other as it should be on both sides. Either way, 4 Auto it doesn’t happen I assume.

That's correct. Wheel spin shouldn't be an issue in 4 auto unless you're on sheer ice.

 

[themust]

Good thread. I can see using 4 Auto more regularly now when I know I'm going to need that quick acceleration in situations that will especially challenge traction. I installed the Helwig 7709 anti-sway bar a few weeks ago and found that the inside rear wheel lost traction a lot more easily in hard acceleration involving turns and undulations. Leading, of course, to loud inadvertent tire squealing. (This is due to the more limited articulation of the axle with the bigger sway bar).

 

[HSKR R/T]

When you get wheel spin when in 2 HI, is it both rear tires or does just one tire spin? If it's both tires your diff is working fine. You just need to learn how to put the power down without spinning the tires. If just one wheel spins there's something wrong with your diff.


The anti-spin diffs act as a limited slip differential. Some used to call it posi-traction back in the day. It's supposed to keep one wheel from spinning on its own, aka one wheel peel. One tire might spin a little before the diff reacts, but for anything more than a chirp both wheels should spin.

Dodge has never called in posi-traction, that's a GM name for the same thing. Dodge has always been limited slip, untik recently when they started calling it anti-spin.

That being said, limited slip, anti-spin, posi, whatever you want to call it, in situations where there is a large difference in traction, such as one tire on solid pavement and one in gravel, if you punch the gas pedal, you will overcome the clutch friction, and only the tire with less traction will spin.