Shifting into 4wd, on the fly?

[ej132]

Hello,
Recently picked up a 17 5.7 slt.

quick question on shifting into 4wd, has the electric shift, three position switch

2wd
4wd lock
and 4 low

Im a jeeper so I know 4 low is not on the fly or at least in jeep its barely crawling

But my question is does this system allow shifting while moving and in drive? Or is it like the older fords that it has to be stopped in neutral ?

Thanks, just dont wanna tear something up on this new truck

 

[OutlawTrucker]

You can do all on the fly but 4L

 

[WilliamS]

I think 4hi has a max speed but I think its near 50. Other than that you just put in 4hi and it will get there. If you are heavy on the throttle it wont shift to 4hi till it meets certain conditions.

 

[ivey_usmc]

This is good. I never knew, Ivel always stopped and put it in neutral first.

 

[ej132]

Ok thank you all for the info.

On a side note, any one know why on the 4 hi it says "lock"? I know it doesnt have lockers, is this just a lingo thing dodge did?

 

[John Jensen]

It says "lock" to differentiate between "auto" and "lock".
When in "auto" it is in 2wd until a need for 4wd is sensed.
In "lock" it is always in 4wd.

 

[smurfs_of_war]

And when you shift let off or feather the gas a bit, seems to engage quicker.

Sent from my SM-G935W8 using Tapatalk

 

[ej132]

Ok so if mine doesnt say specifically 4 auto my truck doesnt have that feature correct?

 

[ColdCase]

Yes, it just physically engages the gears to lock the front and rear drive shafts. There is some synchronization to keep it from clunking and grinding, so its shift on the fly. As someone mentions, easing up on the throttle may make the process smoother. I don't think there is a speed restriction, although that could vary by year.

The auto case is different, but it would have a auto position on the switch.

 

[baum]

Ok so if mine doesnt say specifically 4 auto my truck doesnt have that feature correct?

correct! you just have 4-hi, 4-lo and 2wd

 

[ej132]

Ok awesome for answering that all, had a 99 durango with the full time 4wd which was a mechanical system rather than sounds like this is electrical and only turns on when slippage is detected but I loved it on the durango, but not a big deal this truck doesnt have it thanks

 

[ColdCase]

Just to be clear, FCA used two transfer cases in the 1500, the base simple case, and the more complex auto case.

Auto means that it only engages when slip is detected. You don't have auto, so your base transfer case locks in just like your 99. Instead of a mechanical lever to move the shift fork, an electric motor moves the fork for you, based on the mode selected.

 

[CrispyBacon]

It says "lock" to differentiate between "auto" and "lock".
When in "auto" it is in 2wd until a need for 4wd is sensed.
In "lock" it is always in 4wd.

More accurately, on the trucks that DO have 4auto and 4 lock, they both do the same thing. 4auto=4lock because of the way the system works. Nothing ever actually locks up on those transfer cases, not even in 4 low.

 

[ej132]

More accurately, on the trucks that DO have 4auto and 4 lock, they both do the same thing. 4auto=4lock because of the way the system works. Nothing ever actually locks up on those transfer cases, not even in 4 low.

Front and rear drive shafts lock together but the open diffs (or lsd in the back?) makes it act like most 4wd systems ever sold.

 

[Jeepwalker]

In the winter with your system if you drive it in 4-lock on dry pavement or pavement that's mostly dry, some driveline binding will occur but most of the 'slippage' which will occur will just happen imperceptibly and you'll never know it. But around sharper turns like going into driveways where the radius of each tire is vastly different (and the distance each travels) that difference in length is going to cause the wheels to skiff and you will probably feel some driveline binding. If you're turning on a snowy road, the wheels can slip easier. Of course the engineers (we hope) design the system to be able to handle this, but just be aware, try not to make sharp turns on dry pavement in the "lock" position. It's when ya run larger than stock tires that the strain can overload the system.

In snow driving in Jeeps with the Select-trak xfer case, the "Full-Time" position was great for worry-free normal driving on partially snowy roads because you still apply driving force to the front wheels for increased stability w/o axle 'wind-up', but 'Part-time' (Locked) gave a lot more stable feeling and better control in deeper snows IMO. Our Grand Cherokees in the locked position were extremely good in snow!

 

[Jeepwalker]

Front and rear drive shafts lock together but the open diffs (or lsd in the back?) makes it act like most 4wd systems ever sold.

Agreed .....except he has the benefit of 'traction control' at low speeds.


The "auto" mode is great when you were driving on paved roads with mixed patches of snow, dry pavement, wet pavement, then more snow/ice/slush again. You still get driven power to the front wheels and significantly increased stability. That probably constitutes 90% of the 'typical' inclement winter driving conditions for the rural and city commuter where the roads are generally kept fairly clean after snows and ice. The last couple years around here (in WI) I can count on 1 hand where we had enough snow to REALLY need the "locked" position. Of course some years there are many more large snows. For those handful of times when it REALLY snows (or if you live in the mountain states), and you're driving in accumulated snow, or ranchers going out to the back 40, 4-lock provides greater stability still. In summer muddy conditions when pulling a trailer up an incline or muddy track locked is definitely the way to go.

I bet the majority of 4x4 vehicle owners (maybe not Ram owners) don't have a clue what the difference is between auto and locked or what axle windup even is, so Auto is a great system, they can set it and forget it. It doesn't really add a ton more wear to the system. Lots of vehicles have awd and go 200k+ miles, including our Jeep which just went over 200k and it's all tight still and a previous Jeep that only needed new front u-joints and driveshaft at about 250k mi. I tore the transfer case apart at close to 300k to have a look maybe install new bearings, but it all looked great inside and I just buttoned it back up and put it back in. I bet Dodge gets a bunch of calls every fall after the first snow, people coming in saying their truck/SUV has a problem and 'feels funny'. Probably why Jeep decided to label their system as Part-time and Full-time so newbie 4x4 owners could keep it straight in their mind (course it confused the heck out of everyone else!).

Mine is like yours and doesn't have the 'auto' mode. Wish it did. If you understand 4wd systems, there's a time and place for it.

 

[ColdCase]

Front and rear drive shafts lock together but the open diffs (or lsd in the back?) makes it act like most 4wd systems ever sold.

Unlike the older style auto cases, the newer BW auto transfer cases used in the 1500 don't lock until rear wheel spin is detected, regardless of mode switch setting. Its entirely a mechanical operation besides a 2WD/4WD fork motor.

See http://www.ramforum.com/f38/4wd_lock_4wd_auto-57116/

You can't safely power through a slush pile built up between lanes with the type of auto case used in the RAM, as there is no power driving the front wheels so you hydroplane. Some other auto cases preload the front axle which is better. Locking the axles together and letting the tires slip to mitigate windup works best, for that situation.