New Gladiator Owner, Question Regarding 4H and 4Lo

[benji_style68]

Hey guys,

As of today i own a 2021 Sport S gladiator. I had a couple questions regarding the 4wd options hoping someone could advise.
I previously had owned cars that were strictly AWD for reference and did not have to think about it.

These questions are directed more towards bad weather like snow/ice and not really the off road aspect:
1. Is the gladiator always in that "AWD state" where any of the tires that can pick up traction or will it sit in 2wd until shifted to something else?
2. When to use 4 hi and 4 lo exactly?
3. It seems to put it in 4 lo you would be in neutral, braked and then swap to 4lo from a standstill?
4. 4hi to my understanding is while it is in drive at around 10mph you would swap to it?

If anyone could explain these I would greatly appreciate!

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[Alans17]

1. This is an option on 2021 Gladiators, but not standard. By default, you need to manually shift. AWD is different from 4WD, though.
2. Both 4H and 4L are best suited to off road conditions or snow when it fully covers pavement.
3. Yes, you need to be in neutral to switch to 4L. You can be stopped or slowly rolling forward when you shift, but you need to be in neutral.
4. Yes, you can shift into 4H while in drive. I don’t know what the top speed is for shifting, but I’ve probably done it at 20 before and nothing funky happened.

 

[Kevin_D]

4. Yes, you can shift into 4H while in drive. I don’t know what the top speed is for shifting, but I’ve probably done it at 20 before and nothing funky happened.

The manual, which has all this information within, recommends less than 55mph for 4HI operation.

Kevin

 

[jsalbre]

In addition to the comments above, while you can shift into 4L from a standstill it’s much easier to do it while the transmission is in neutral and you’re rolling at about 2-3 mph. Shifting it while stopped can take some force and is hard on the tcase shifter.

 

[Trippin01]

for mixed snow and pavement, personally I would recommend 2hi with traction control. 4 wheel drive in a JT has no computer monitoring traction control at every wheel like an All Wheel Drive. It is purely mechanical. Its a different monster in the snow. Go to a nice big parking lot and practice. Unless the snow is deep, I prefer my front wheel drive commuter car when there is just light or broken snow floor.

 

[Ohio JKU]

There is a computer system across the axles monitoring wheel speed...

Command trac is the name of the system. Here is a mopar produced video link:

4high is the mos similar to awd... except should not be used on dry pavement... see above and video. Do some searches for “command trac” and alsogo through the manual.

 

[Trippin01]

There is a computer system across the axles monitoring wheel speed...

Command trac is the name of the system. Here is a mopar produced video link:

4high is the mos similar to awd... except should not be used on dry pavement... see above and video. Do some searches for “command trac” and alsogo through the manual.

I do not have the command trac on mine., it does sound nice tho

 

[jsalbre]

I do not have the command trac on mine., it does sound nice tho

Command-Trac is the standard 4wd system on Gladiators (and Wranglers). Do you have Selec-Trac (identifiable by a “4Auto” position on the transfer case shifter)?

 

[benji_style68]

1. This is an option on 2021 Gladiators, but not standard. By default, you need to manually shift. AWD is different from 4WD, though.
2. Both 4H and 4L are best suited to off road conditions or snow when it fully covers pavement.
3. Yes, you need to be in neutral to switch to 4L. You can be stopped or slowly rolling forward when you shift, but you need to be in neutral.
4. Yes, you can shift into 4H while in drive. I don’t know what the top speed is for shifting, but I’ve probably done it at 20 before and nothing funky happened.

How do i know if mine has it (for answer 1)

 

[benji_style68]

Command-Trac is the standard 4wd system on Gladiators (and Wranglers). Do you have Selec-Trac (identifiable by a “4Auto” position on the transfer case shifter)?

So on my window sticker it does say "Command Trac Part Time 4wd system" is this essentially AWD?

 

[Undecided]

Adding to this, can someone tell me more about the LSD and when it 'kicks in'?
Does it only work in 4H or 4L? Do I have to have traction control off or on? Does it detect the spin nearly instantly, or do I need to let a tire spin for 2-3 seconds for it to "kick in"?

I can't find a spot in the manual that talks about the details. Only one tiny paragraph.

The context I am asking is just backing up a wet grass hill earlier this week in 2H I kept sliding with my back driver tire. I was expecting the LSD to "kick in" and let me keep going up but it never seemed to - I went into 4HI to keep going up.

But would I have needed to just turn Traction Control off to use the LSD?

 

[jsalbre]

So on my window sticker it does say "Command Trac Part Time 4wd system" is this essentially AWD?

Command-Trac is Jeep’s traditional part-time 4wd system. It’s either completely on or completely off, and when on both front and rear axles are locked together. This isn’t like AWD and shouldn’t be used on dry pavement as it will cause driveline binding. It would be very rough on tires, hard to turn, and some say it will damage the driveline, though I’ve never actually seen an example of that.

This video helps explain it:

Adding to this, can someone tell me more about the LSD and when it 'kicks in'?
Does it only work in 4H or 4L? Do I have to have traction control off or on? Does it detect the spin nearly instantly, or do I need to let a tire spin for 2-3 seconds for it to "kick in"?

I can't find a spot in the manual that talks about the details. Only one tiny paragraph.

The context I am asking is just backing up a wet grass hill earlier this week in 2H I kept sliding with my back driver tire. I was expecting the LSD to "kick in" and let me keep going up but it never seemed to - I went into 4HI to keep going up.

But would I have needed to just turn Traction Control off to use the LSD?

So on my window sticker it does say "Command Trac Part Time 4wd system" is this essentially AWD?

So the LSD is always active, in that there’s nothing you need to do to enable it. It works based on differences in wheel speed between the left and right wheels on the rear axle. It only affects the rear axle and it won’t do anything if both rear wheels are spinning. A trick that can work sometimes is to pull up one click on the hand brake to put some drag on a spinning wheel, helping the LSD out some torque down, but this does put wear on the hand brake pads. If you can get up it in 4WD without doing that then that’s the way I’d go.

Here’s some good info about how the Trac-Loc works:
https://ballisticparts.com/trac-lok-differential-rear-axle/

 

[ACAD_Cowboy]

So on my window sticker it does say "Command Trac Part Time 4wd system" is this essentially AWD?

Command-Trac is part time 4wd. When you shift from 2 Hi to 4 Hi you lock the power being sent to the front and rear axle. It is an on/off system with 50/50 power split.

When you shift to 4 Lo you get an additional gearing advantage at the expense of greatly decreased speed in gear.

4 Hi can be used on wet or slick pavement but should not be used on dry pavement. It is also very useful on soft or loose surfaces. The reason for no dry pavement is with the locked transfer case, you will get what is called axle wind up and with no way to dissipate this windup things can break.

4 Lo should never be used on dry pavement except in very limited situations, wind up happens far faster and breakage can be more severe.

Select-Trac allows the system to decide when to engage and disengage 4wd based on wheel slip and with the ability to control wind up by disengaging 4wd on the fly it acts as a full time 4wd. It is not as advanced as a full time AWD system which uses a center differential in addition to front and rear differentials but it works well enough.

Adding to this, can someone tell me more about the LSD and when it 'kicks in'?
Does it only work in 4H or 4L? Do I have to have traction control off or on? Does it detect the spin nearly instantly, or do I need to let a tire spin for 2-3 seconds for it to "kick in"?

I can't find a spot in the manual that talks about the details. Only one tiny paragraph.

The context I am asking is just backing up a wet grass hill earlier this week in 2H I kept sliding with my back driver tire. I was expecting the LSD to "kick in" and let me keep going up but it never seemed to - I went into 4HI to keep going up.

But would I have needed to just turn Traction Control off to use the LSD?

Your limited slip differential (LSD) is a spring loaded clutch pack in the differential carrier. It is purely mechanical. When the driven wheel slips the clutch pack reacts and locks the differential momentarily to drive the opposite wheel. When in good shape it will provide somewhat seamless axle locking and unlocking. It is not as strong as a dedicated axle lock but it is intended for momentary sporadic use and not a solution to climbing a shale bank at WOT.

The fancy modern systems can help an LSD out with something called a Brake Lock Differential which uses the ABS system to brake the "free wheel" to induce the LSD to lock up and drive both wheels. This is a natural part of the stability control system and when it sees both, now driven wheels, spinning relative to the opposite axle it start freaking out and chopping power etc because it thinks you're sliding. In these cases, turn off stability and/or traction control and shift into 4 Hi to gain maximum use of the power available. Worst case putting it in 4 Lo does the same with more gearing for more mechanical advantage.

 

[Undecided]

Command-Trac is part time 4wd. When you shift from 2 Hi to 4 Hi you lock the power being sent to the front and rear axle. It is an on/off system with 50/50 power split.

When you shift to 4 Lo you get an additional gearing advantage at the expense of greatly decreased speed in gear.

4 Hi can be used on wet or slick pavement but should not be used on dry pavement. It is also very useful on soft or loose surfaces. The reason for no dry pavement is with the locked transfer case, you will get what is called axle wind up and with no way to dissipate this windup things can break.

4 Lo should never be used on dry pavement except in very limited situations, wind up happens far faster and breakage can be more severe.

Select-Trac allows the system to decide when to engage and disengage 4wd based on wheel slip and with the ability to control wind up by disengaging 4wd on the fly it acts as a full time 4wd. It is not as advanced as a full time AWD system which uses a center differential in addition to front and rear differentials but it works well enough.



Your limited slip differential (LSD) is a spring loaded clutch pack in the differential carrier. It is purely mechanical. When the driven wheel slips the clutch pack reacts and locks the differential momentarily to drive the opposite wheel. When in good shape it will provide somewhat seamless axle locking and unlocking. It is not as strong as a dedicated axle lock but it is intended for momentary sporadic use and not a solution to climbing a shale bank at WOT.

The fancy modern systems can help an LSD out with something called a Brake Lock Differential which uses the ABS system to brake the "free wheel" to induce the LSD to lock up and drive both wheels. This is a natural part of the stability control system and when it sees both, now driven wheels, spinning relative to the opposite axle it start freaking out and chopping power etc because it thinks you're sliding. In these cases, turn off stability and/or traction control and shift into 4 Hi to gain maximum use of the power available. Worst case putting it in 4 Lo does the same with more gearing for more mechanical advantage.

Thank you! I knew it was mechanically done but still incorrectly thought it had to somehow be 'turned on' like a full locker.

So in my case a few days ago, I am guessing I did not let it 'spin' long enough to fully engage. Maybe a wrong habit of once I feel spinning I instantly let off the gas. I was expecting the LSD to take affect basically instantly.

What you said reads to me that instead I should have held it just a second or two longer to let the brake locking and springs in the diff actually take affect.

OR! the passenger tire also spun on me once the LSD kicked in and I didn't not notice, which makes the LSD useless and why I needed 4HI. That is possible.

 

[ACAD_Cowboy]

It does need to spin to work, it is not a from zero RPM thing like a locker. And if both wheels spin you go nowhere anyway.

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