Confused Newb: Rubicon 4H/L and Lockers

[InMyImage]

I just got a free... oops sorry, my bad... my daughter just bought a 2019 Rubicon JLU. My brother is active in a Midwest club and she really wants (ok we both want) to hit the dirt with him and hopefully some locals to central Indiana as he lives an hour North of Chicago.

We were going back and forth trying to decide between the Sport S or a Rubicon. He recommended getting a Sport S and building it the way she wants it but after digging into everything he was recommending, in the end the cost was going to be similar but you still wouldn't have the lockers or an electric sway bar disconnect.

Given we don't know anyone local into the Jeep scene and he lives 4+ hours away she decided to get the Rubicon because she didn't want to spend all her time with him for the next year just modifying the Jeep and still not have the same capability so she bought the Rubicon.

Of course it is raining today and normally in her old Mitsubishi Outlander Sport if it rained hard or during the entirety of winter she ran in 4wd and if snow was bad switched to 4wd Lock so the topic of what to do in the Jeep came up.

Reading the manual it says for the 4 position transfer case:

Four-Wheel Drive High Range — This range maximizes torque to the front driveshaft, forcing the front and rear wheels to rotate at the same speed. This range provides additional traction for loose, slippery road surfaces only.​

I was under the impression that in 4H and 4L that both axles would get even power but each wheel would be subject to spinning if it was left hanging in the air and that both wheels would only truly spin together if the locker was engaged.

So, am I seriously confused, reading the manual wrong, found an error in the manual or just simply overly tired and need more coffee?

Thanks

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[Rploaded]

It’s says the front and rear wheels which is correct. The wheel with the least traction on each axle would still spin if in the air. Lockers however would fix that issue.

 

[Stormin’ Moorman]

When you put it in 4H or 4L the transfer case directs 50% of the power to the front and 50% to the rear. It can still cut power to one wheel in front and one wheel in back. If you high center and get one front and one rear wheel off the ground you're stuck, even though the remaining two wheels may have traction. Locking up directs 25% of the power to each wheel. So all 4 wheels spin 100% of the time.

PS- pretty jeep

PPS- you can't run the 4wd in the Rubicon like she did in her other car. It's for part-time use only. Do not run the 4wd on pavement or when you have traction. That's bad

 

[InMyImage]

Thanks everyone. Glad my initial understanding was correct otherwise I would have regretted not pushing her to go the sport route!

Will make sure she knows to only use the 4wd if there is actual snow on the road. She's a teacher with a 45 minute commute and early in the morning it is common to have packed snow on the road. Fortunately when that happens it is rare to get over 45 which I saw should be ok.

 

[Young04]

Thanks everyone. Glad my initial understanding was correct otherwise I would have regretted not pushing her to go the sport route!

Will make sure she knows to only use the 4wd if there is actual snow on the road. She's a teacher with a 45 minute commute and early in the morning it is common to have packed snow on the road. Fortunately when that happens it is rare to get over 45 which I saw should be ok.

I have found that 4WD is needed less frequently than one may think. My JLUR did fine with mostly 2Hi this winter.

 

[Young04]

Thanks everyone. Glad my initial understanding was correct otherwise I would have regretted not pushing her to go the sport route!

Will make sure she knows to only use the 4wd if there is actual snow on the road. She's a teacher with a 45 minute commute and early in the morning it is common to have packed snow on the road. Fortunately when that happens it is rare to get over 45 which I saw should be ok.

Also, those KO2s stop pretty well in snow (I say this as someone who has a good deal of experience with winter tires - I run Nokian Hakkas on two of my other vehicles).

 

[InMyImage]

I have found that 4WD is needed less frequently than one may think. My JLUR did fine with mostly 2Hi this winter.

I'm thinking the AT KO2's are going to work well in the snow, she's just used to putting her old car in 4wd and forgetting it unless things are bad and then switching to 4wd lock.

 

[Thill444]

I have found that 4WD is needed less frequently than one may think. My JLUR did fine with mostly 2Hi this winter.

Exactly. I told my wife not to switch to 4H unless she gets stuck or is losing traction. I don't have a Rubicon (Unlimited Sport S) but I am putting snow rated Dick Cepek AT tires on it (33"). Here in New England they keep the roads plowed really well, so I suspect 2H will be used 90% of the time.

 

[Gallagher]

Also, you probably know this already, but the lockers only work in 4lo unless you have a Tazer or similar. I would say don't run around in 4hi if it's raining, only if it's snow or offroad.

 

[D60]

It should read front and rear DRIVESHAFTS

It's a part-time system so there is no center diff, ie differential in the transfer case.

Full-time systems typically utilize a center diff so you don't get the binding on dry surfaces when in "four wheel drive."

So, in the Wrangler in 4wd the differentials in each axle dictate which wheel(s) are forced to spin if traction becomes scarce.

 

[D60]

You can totally use 4hi in any situation other than dry pavement, as you see fit. Even rain allows for just that tiny bit of slippage necessary to relieve drivetrain wind-up that you would encounter on dry pavement (it loads up the chain in the t-case and can theoretically stretch it over time)

 

[Uhdinator]

Read up on the traction control features. The Brake lock differential works very well and applies braking to a spinning tire to stop it from spinning and transfer power to the other wheel that has traction. Its almost as good as having a locker.....you just have to learn how it works and use the right technique and it will do well.

Lockers are for 4L range off road........not for driving in snow. The brake lock differential feature and traction control will take care of street driving on packed snow and Ice in 4H range.

I had a 2003 TJ Rubicon and rarely used the lockers, and it had no traction control features. I now have a Sport with no lockers and have taken it places I used to go with the Rubicon. The BLD works very well.....if you get where you can't move due to a spinning tire.......you gradually increase throttle (gently) until the wheel with traction starts to grab. Don't be too aggressive on the throttle or when it grabs you could launch into the trees.

https://blog.fcanorthamerica.com/2008/02/11/jeep-brake-traction-control-explained/

 

[D60]

While I haven't had a reason to mess with the JL yet, I would kick my TJ in and out of 4 hi at speeds as high as 80 mph. If the JL can't handle that kind of use (abuse?) I'm going to have a bad time.

Nothing abusive about that

 

[ToolMan514]

You could learn a little about the Rubicon Rock-Trac 4WD system in this Jeep video:

 

[ToolMan514]

There has been some great info already here, so this might sound like an echo.

The BFG KO2s are just fine for winter, coming from Quebec which requires winter-rated tires for 4 months of the year. I use 4H any time I'm not on dry pavement in the city -- It helps to pull the Jeep forward when turning or from a stop and reduces the amount of spinning that I get. The only time I used 4L in winter was when parking on top of snowbanks and using the lockers. Winter conditions are different everywhere though, so my experience in Canada and upstate NY may not compare to you.

Have fun with your Jeep!

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