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When to use 4 Hi

Claymore

Member
Joined
Dec 13, 2021
Messages
81
Location
Portland, Michigan
When the road is covered with snow can I shift into 4 Hi, and drive normally?
If there are dry patches do I need to go back to 2Hi?
How fast can I drive in 4 Hi?
I have a 2018 wrangler JKU if that makes a difference in capabilities.
 

BLACKJKU

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Feb 22, 2020
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3,499
Location
Huntington In
When the road is covered with snow can I shift into 4 Hi, and drive normally?
If there are dry patches do I need to go back to 2Hi?
How fast can I drive in 4 Hi?
I have a 2018 wrangler JKU if that makes a difference in capabilities.

4 High is for slick roads, you can drive on wet roads when in high as long as your not making alot of turns. Having the open carrier isn't as bad on wet roads as would be a front axle with a locker.

You can drive as fast as you want but why? If the roads are bad enough for 4wd then you shouldn't be going fast.
 
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OP
Claymore

Claymore

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Joined
Dec 13, 2021
Messages
81
Location
Portland, Michigan
I was thinking top speeds of 25-30.
I didn't go with the locker in the front.
I had a conversation with some guys that were under the impression that 4 Hi could be used on all road conditions.
You confirmed my belief that 4 Hi is for off road or when 2 Hi. Doesn't provide enough traction. In other words, it's not like all wheel drive.
 
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BLACKJKU

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Feb 22, 2020
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Huntington In
I was thinking top speeds of 25-30.
I didn't go with the locker in the front.
I had a conversation with some guys that were under the impression that 4 Hi could be used on all road conditions.
You confirmed my belief that 4 Hi is for off road or when 2 Hi. Doesn't provide enough traction. In other words, it's not like all wheel drive.

4High is for on the highways when needed and Offroad when the extra traction is needed for mud and hills. You can use 4 High on dry roads but why?
 

fast6

New Member
Joined
Jan 16, 2022
Messages
7
Location
Ontario Canada
You can drive as fast as you want but why? If the roads are bad enough for 4wd then you shouldn't be going fast.
Why cant people just answer the question and hold the preaching!
Some of us live in areas where winter is a long season and we drive in the snow at highway speeds (safe speeds) but still highway speed and in somewhat snowy conditions.
Just answer the question and keep the "advice" for your own posts lol
 

MacGuyver

JK Enthusiast
Joined
May 13, 2020
Messages
803
Location
Wisconsin
Why cant people just answer the question and hold the preaching!
Some of us live in areas where winter is a long season and we drive in the snow at highway speeds (safe speeds) but still highway speed and in somewhat snowy conditions.
Just answer the question and keep the "advice" for your own posts lol
While I hear what you are saying, I've never seen this response as preachy. All level of knowledge comes to these forums and advice is what many are looking for. This response to me is directly in line with question that was asked.

Many don't know that all wheel drive is not that same as four wheel drive. Based on people I see in the ditch following a snow storm, people with four wheel drive can get a false sense of security on slippery roads. Comments like that may save one person a tow truck bill.

Personally to answer the question, I flip back and forth depending on what the road is like, and how many turns on it. I try not to use 4wd on dry roads.
There is no max speed for 4wd, but as stated there usually isn't a reason for it at high speeds. Also, given that the front and rear wheels spin at the same speed, going high speed can be not great for the transfer case, especially on dry roads. I tend to limit it to around 40 mph, but usually much less. Unless the roads are covered in snow, then I'm 4wd the whole way.
 

xackley

JK Enthusiast
Joined
Nov 29, 2019
Messages
138
Location
finger lakes of NY
What I always liked about 4 wheel drive is that it allowed me to go slower. Less need for momentum. Less spinning and rocking to get moving.
4 low is for super control, like going down a steep slippery hill where avoiding the brakes is a good idea. Or when slow navigation is required. Or when low speed with lots of power is required.

Don
 

fast6

New Member
Joined
Jan 16, 2022
Messages
7
Location
Ontario Canada
While I hear what you are saying, I've never seen this response as preachy. All level of knowledge comes to these forums and advice is what many are looking for. This response to me is directly in line with question that was asked.

Many don't know that all wheel drive is not that same as four wheel drive. Based on people I see in the ditch following a snow storm, people with four wheel drive can get a false sense of security on slippery roads. Comments like that may save one person a tow truck bill.

Personally to answer the question, I flip back and forth depending on what the road is like, and how many turns on it. I try not to use 4wd on dry roads.
There is no max speed for 4wd, but as stated there usually isn't a reason for it at high speeds. Also, given that the front and rear wheels spin at the same speed, going high speed can be not great for the transfer case, especially on dry roads. I tend to limit it to around 40 mph, but usually much less. Unless the roads are covered in snow, then I'm 4wd the whole way.
All I was trying to say was that in all forums, when people ask a question so many times the answers get sidetracked to "advice" on somewhat unrelated topics and the OP never gets the answer he/she was looking for. The answer you just gave was detailed and totally covered his question. I was just reading a few questions in multiple posts that related to things I wanted to know and every question/topic got derailed by someone's offering their "opinion" on something other than what the original question was. We are fortunate to have such a wide group of owners , from many locations, with everything from stock to heavily modified jeeps. When I use search and look for a topic of interest to me, it's frustrating when the answers don't reflect the question.
 
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Vman

JK Enthusiast
Joined
Aug 23, 2021
Messages
399
Location
Pacific NW
I was thinking top speeds of 25-30.
I didn't go with the locker in the front.
I had a conversation with some guys that were under the impression that 4 Hi could be used on all road conditions.
You confirmed my belief that 4 Hi is for off road or when 2 Hi. Doesn't provide enough traction. In other words, it's not like all wheel drive.

The main problem with engaging 4wd on dry roads is when you try to turn and your wheels are all going the same speed. It causes stress on your driveline components. Try 4h at slow speeds in a parking lot. You'll feel the resistance and the wheel hop.
 
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MacGuyver

JK Enthusiast
Joined
May 13, 2020
Messages
803
Location
Wisconsin
All I was trying to say was that in all forums, when people ask a question so many times the answers get sidetracked to "advice" on somewhat unrelated topics and the OP never gets the answer he/she was looking for. The answer you just gave was detailed and totally covered his question. I was just reading a few questions in multiple posts that related to things I wanted to know and every question/topic got derailed by someone's offering their "opinion" on something other than what the original question was. We are fortunate to have such a wide group of owners , from many locations, with everything from stock to heavily modified jeeps. When I use search and look for a topic of interest to me, it's frustrating when the answers don't reflect the question.
I've been frustrated by similar things, and these forums certainly aren't immune to it.
 

GP Noir

Member
Joined
Feb 6, 2022
Messages
46
Location
Wolf Hollow
How fast can one drive in 4 Hi? As fast as conditions allow.

What need does one have to drive highway speeds in 4 Hi? We drive at highway speeds in 4 Hi all the time and have done so safely on interstate trips in our Grand Cherokee. Of course, the Grand Cherokee has Full Time 4wd.

There are two types of 4 wheel drive. First, is Part Time Four Wheel Drive. Driving on dry pavement (or other smooth high traction surface) isn't recommended by the factory. That's because the transfer case locks the front & rear driveshaft together to turn at the same RPM. This can lead to driveline windup because the front and rear axles don't always turn at the same RPM.

The same isn't true for the tires if the Jeep is equipped with open gears. Open gears let the left and right tires of the axle turn at their own RPM, biasing torque to the wheel with the higher speed. However, that changes if you lock the axle shafts to each other.

The second is Full Time Four Wheel Drive. Full Time Four Wheel Drive has a T case that allows the front & rear to turn at their own RPMs. I'm not sure what mechanism is used to allow the differential in RPM, But I do know from experience that in Full Time 4WD isn't as effective in loose traction.

Although All Wheel Drive drives uses a differentiating T case and is the same thing as Full Time 4WD, the 4WD T case has a low range. All Wheel drive doesn't.

Our Grand Cherokee T case has Full Time 4WD, Neutral and 4 LO (which I believe is part time). The GC also has traction control. Highway speeds in 4 Hi is normal.

In regards to the question @Claymore has- I think he means "How fast can I drive safely in Part Time 4WD?" The answer is, no faster than driver's skill & experience and conditions allow. What those limits are can only be carefully determined by the driver. In my experience, driveline windup is less severe in a rig with a longer wheelbase. But again, that's something you have to determine for yourself.

In my Cherokee, I've driven at highway speeds in Part Time 4WD on highways in the rain, ice and snow with patches of dry pavement in between. Speeds were, of course, limited by prevailing conditions. I've also driven at less prudent speeds on smooth fire roads. For years, my daily driver was an XJ with an ARB in the front and a Detroit in the rear.

I paid the cost in increased driveline wear, but the extra control Part Time 4WD afforded on the street in adverse and varying conditions has been worth it.
 
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Vman

JK Enthusiast
Joined
Aug 23, 2021
Messages
399
Location
Pacific NW
I've been frustrated by similar things, and these forums certainly aren't immune to it.

Text environment is like email. How often do we get an email and the initial reaction is to get pissed off?

Not a great way to communicate, even if you're good at the mechanics of it. Pun intended.