2020 JLU. 4WD operation.

[Arif]

This is the first 4WD car am driving. All previous cars were either FWD, RWD, or AWD. Maunual recommends to not switch from 2H to 4H, if it is hard surface dry road. Toronto gets a lot of snow. How to handle black ice, while driving and switching from 2H to 4H, without being detrimental to the 4WD system ? Black ice is hard, but dont know when one hits on the road, and it could be multiple times. I would like to drive in 4H mode during winter with snow and icy conditions, but the snow and ice come in patches, while the rest of the time I am hitting hard dry road (but dont know when I would hit a hard snow or black ice patch, while driving), and I am afraid to drive in 4H mode as the manual warns not to do so as it is bad, and will damage the drive system. How does one handle this in winter ?

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[omi205]

Good post. I think that the warned damage comes into play when you are at higher speeds, like 40-50mph+ when in 4h. Clearly 4L is for very low speeds. Like 5mph max 10mph. With regard to black ice. I dont know if 4h will truly help in these scenarios. But is more helpful when actually driving on snow covered roads. So if your driving on shoveled roads, you can clearly see the road, and it has random black ice patches, probably better off in 2h. If the road is covered in snow then 4h would be useful. I could be wrong and am interested in what more experienced drivers thought are.

 

[aldo98229]

This is the first 4WD car am driving. All previous cars were either FWD, RWD, or AWD. Maunual recommends to not switch from 2H to 4H, if it is hard surface dry road. Toronto gets a lot of snow. How to handle black ice, while driving and switching from 2H to 4H, without being detrimental to the 4WD system ? Black ice is hard, but dont know when one hits on the road, and it could be multiple times. I would like to drive in 4H mode during winter with snow and icy conditions, but the snow and ice come in patches, while the rest of the time I am hitting hard dry road (but dont know when I would hit a hard snow or black ice patch, while driving), and I am afraid to drive in 4H mode as the manual warns not to do so as it is bad, and will damage the drive system. How does one handle this in winter ?

I see you have a Sahara. Does it have the optional Selec-Trac? One way to tell is if the 4WD shifter shows an 4H AUTO mode next to the 4H PART TIME —see below. Selec-Trac’s AUTO mode works like AWD: in RWD in normal conditions; automatically engages 4H if it senses the front wheels slipping.

If your Sahara has the standard Command-Trac, you can safely drive in 4H PART TIME up to 55 or 60 MPH I believe —there should be an explanation in the Owner’s Manual. Just avoid tight turns on dry pavement. If the front hops due to binding, it’s not the end of the world. The Jeep can take it. Just don’t make a habit of it.

Finally, a Jeep Wrangler with a rear limited-slip differential (LSD) and a good set on tires, such as BFG KO2, GY Duratrac or General ATX, will get you through most snow conditions without even engaging 4WD. If your Jeep didn’t come with LSD, adding a Detroit True-Trac is relatively inexpensive. Those things are known to be virtually indestructible.

Good luck.

 

[viper88]

Good post. I think that the warned damage comes into play when you are at higher speeds, like 40-50mph+ when in 4h. Clearly 4L is for very low speeds. Like 5mph max 10mph. With regard to black ice. I dont know if 4h will truly help in these scenarios. But is more helpful when actually driving on snow covered roads. So if your driving on shoveled roads, you can clearly see the road, and it has random black ice patches, probably better off in 2h. If the road is covered in snow then 4h would be useful. I could be wrong and am interested in what more experienced drivers thought are.

Saharas with Select Track can leave in in Auto 4H when it's snowy or icy.

We get a fair amount of snow here in the Chicago area. I have owned Wranglers equipped with A/T tires and driven in every imaginable winter situation over the last 30 years. The weight of a Wrangler and it's ground clearance does pretty good on snow even with A/T tires. 95% of the time 2H is what I use. I have never engaged 4H in the rain. Only time was in deep snow. Even then there usually is not problem unless the snow is more then 8"-12". The only time I engaged 4H was to get unstuck or in very deep snow, 10"-12" deep. I usually go back to 2H once I am unstuck. I have never used 4L on the street. Caution should be used on any ice covered roads. The best thing for icy roads is dedicated winter tires.

I think my stock K02"s should be as good or better then my past A/T tires since they are winter rated with the snowflake emblem.

 

[TrailJoy]

Seeing that you live in Toronto, I'm going to assume that you got the cold weather package. Did you by chance get the Northern package instead? If so, then you would have the select track (4H auto), as shown in the picture above. I leave mine on all winter long, so long as there is snow or ice on the ground. I also can't say enough about a good DEDICATED winter tire. I hear a LOT of people suggesting an all weather or all season tire for winter (like Duratracs), but I strongly disagree for where I live (Northern BC). A dedicated winter tire (I'll be using Blizzaks this year) can make a world of difference when driving in winter conditions.

 

[Arif]

I do not have the 4H Auto, else I would have used it just like an AWD. I do have the cold weather package that came with the AT tires which I am happy with, to drive in winter. From all the replies, I conclude that driving in 2H most time will do the job, and shifting to 4H on unplowed snow roads will be fine. On a very rare occasion, on unplowed highways, Where speed is 120 Kms/hr, I would need to be careful not to exceed 80kms/hr if I have engaged the 4H mode, or to slow down and shift to the 2H mode and speed up to the highway limit speed. Is it correct that one should not be driving greater than 80 Kms/hr in 4H mode ?? I don’t know if I have LSD - How do I find out ?

 

[Adventure.AS]

... From all the replies, I conclude that driving in 2H most time will do the job, and shifting to 4H on unplowed snow roads will be fine. On a very rare occasion, on unplowed highways, Where speed is 120 Kms/hr, I would need to be careful not to exceed 80kms/hr if I have engaged the 4H mode, or to slow down and shift to the 2H mode and speed up to the highway limit speed. Is it correct that one should not be driving greater than 80 Kms/hr in 4H mode ?? I don’t know if I have LSD - How do I find out ?

Drive defensively and according to the conditions as if you were in a 2WD. If the roads are so bad that you are contemplating using 4H then 80 km/h is too fast anyway. Slow down! There is no good reason to be travelling fast on snowy/icy roads. Remember 4WD can aid in traction, going and steering on roads with loose gravel, for example, but 4WD does absolutely nothing to help with stopping!

 

[aldo98229]

I don’t know if I have LSD - How do I find out ?

Enter your VIN on the link below to pull up your Jeep's factory build sheet.

https://fcacommunity.force.com/RAM/s/equipment-listing

The OPTIONAL EQUIPMENT section (normally after page 5) will indicate whether your JL has a factory installed LSD --"Anti-Spin Differential Rear Axle" in FCA lingo.

Here's an example of my Jeep's build sheet:

 

[Arif]

Thanks all. I do not have LSD.

 

[jaozus]

Just throw on a set of winters and call it a day

 

[The_Phew]

If you want to be moving, but are not moving, shift into 4H until you are moving.

Otherwise, stay in 2H.

 

[TrailJoy]

Thanks all. I do not have LSD.

If you're driving on ice (and snow), no selec-trac and no LSD warrants a high end quality dedicated winter tire, in my opinion. Assuming you know how to drive a RWD vehicle in the winter you should be fine, but with the wrong tire (and lack of skill) those rear tires can become the front tires in a heartbeat, and if that happens the crap in your pants could be the least of your problems.

You have 4WD, so like others have mentioned you should be fine - But get a good winter tire and drive carefully.

 

[word302]

I do not have the 4H Auto, else I would have used it just like an AWD. I do have the cold weather package that came with the AT tires which I am happy with, to drive in winter. From all the replies, I conclude that driving in 2H most time will do the job, and shifting to 4H on unplowed snow roads will be fine. On a very rare occasion, on unplowed highways, Where speed is 120 Kms/hr, I would need to be careful not to exceed 80kms/hr if I have engaged the 4H mode, or to slow down and shift to the 2H mode and speed up to the highway limit speed. Is it correct that one should not be driving greater than 80 Kms/hr in 4H mode ?? I don’t know if I have LSD - How do I find out ?

If you are driving in conditions that you think warrant 4wd at speeds anywhere near 80kmh you're doing it wrong.

 

[GreyFox]

I'm always amazed at the people who think 4WD=God mode when driving

 

[Apoznan]

If you want to be moving, but are not moving, shift into 4H until you are moving.

Otherwise, stay in 2H.

These are the type of comments that keep me coming back.

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