With 4A, what do I need 4H for?

[Heckler]

From my understanding from past vehicles 4A is more like full time 4 wheel drive with a bit more tech involved but basically 4 high your front wheels turn faster than you rear wheels providing more pull up front (just like 4 low with higher gearing) this is why you don’t want to use it in high traction situations as it can bind up your transfer case and cause damage. With 4A or full time 4 wheel drive your front and rear wheels turn at the same speed making it ok to use on pavement/high traction situations.

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[Scott R Nelson]

...but basically 4 high your front wheels turn faster than you rear wheels providing more pull up front (just like 4 low with higher gearing)...

Ummm, no.

Both axles have the exact same gearing - 4.70:1 for my Sasquatch - all of the tires are the same size, and all wheels should turn at the same rate. When going around turns there will be a difference because the front wheels take a longer path than the rear wheels, but going straight all wheels turn at the same rate.

 

[Heckler]

Ummm, no.

Both axles have the exact same gearing - 4.70:1 for my Sasquatch - all of the tires are the same size, and all wheels should turn at the same rate. When going around turns there will be a difference because the front wheels take a longer path than the rear wheels, but going straight all wheels turn at the same rate.

The difference is in the ratio is in the transfer case not the axles. In my last Jeep Cherokee (back in 2001) it had 4Hi and full time 4WD and the selection is made with the transfer which drives the front and rear wheels the same speed, with 4high the front wheels spin a bit faster than the rear, the owners manual specifically stated to never run 4high on pavement for this reason but you could run on pavement with full time 4WD.

Things are a bit different now with the tech now days and 4WD auto will switch between all combinations of wheel drive depending on where traction is needed which is why you can drive in 4wd auto in any condition as the system will adjust as needed.

 

[dgorsett]

Folks always say 4wd helps you go but does help you stop on slick roads, probably true for 4A but not necessarily for 4H. If you manually downshift in 4H you've got 4 wheels gripping on compression with 2wd or (maybe) 4A you've only got the rear gripping.

Probably best that folks believe it doesn't help, too many crazies out there anyway.

 

[BleednBlue]

Holy thread revival Batman Curious, for those that do NOT have 4A, what happens when you choose GOAT mode = Slippery? Guessing it engages 4H?

 

[Roach011]

I'll just add, since this seems to have evolved into a more technical discussion of how 4A works vs 4H - I like to use 4H off road because it is more predictable when driving on varying surfaces at speed. 4A can lead to unanticipated traction gains and losses.

 

[Scott R Nelson]

I'll just add, since this seems to have evolved into a more technical discussion of how 4A works vs 4H - I like to use 4H off road because it is more predictable when driving on varying surfaces at speed. 4A can lead to unanticipated traction gains and losses.

I have never noticed that with mine. I have driven thousands of miles on all types of dirt roads, usually in 4A, but occasionally in 4H. I rarely get over 60 mph on those dirt roads, but I'll go that fast on some of the straight parts.

I'm not sure what a "traction gain" is, but I would recognize a traction loss. Not something that happens enough for me to notice it.

Gratuitous photo of a place where it would be likely to happen if it were going to happen (but didn't):

 

[Beach_Bum]

Holy thread revival Batman Curious, for those that do NOT have 4A, what happens when you choose GOAT mode = Slippery? Guessing it engages 4H?

On my '22 Black Diamond (No 4A), when I selected Sport mode, the transfer case would remain in 2H. I never used Slippery mode so unsure if it would shift to 4H or remain in 2H.

On my '23 OBX with 4A, when I select Sport mode, it shifts to 4A but I manually select 2H afterward.

 

[Roach011]

I have never noticed that with mine. I have driven thousands of miles on all types of dirt roads, usually in 4A, but occasionally in 4H. I rarely get over 60 mph on those dirt roads, but I'll go that fast on some of the straight parts.

I'm not sure what a "traction gain" is, but I would recognize a traction loss. Not something that happens enough for me to notice it.

Gratuitous photo of a place where it would be likely to happen if it were going to happen (but didn't):

By traction gain I just mean that the front wheels engage when the computer decides adding to your traction and that is not something that can be really anticipated.

 

[userdude]

Use 4H when you don't want the computer guessing... The only difference in 4H and 4L is the gearing in the transfer case, so if you're going faster and 4L is unwanted, 4H or 4A are probably mostly interchangeable. But there may come a time when you want to be sure, hence 4H. But you get 4H regardless due to the nature of 4x4. I don't think it's wrong either way, except when it is those few times you (may) need or want it.

I suspect a lot of folks use 4L when 4H would work better, like rubble fields or between obstacles, where the obstacles aren't necessary needing low end slow traction delivery. But it's somewhat a pain to go into 4L, so a lot of folks just switch for the whole ride.

And! In my opinion, if you don't want to run in 4H on pavement, 4A is safer. It's pretty easy to forget that you're in 4H when going home afterwards, whereas 4L it's pretty obvious. Ask me how I know...

 

[dgorsett]

I'd say 4H for sand, deep snow, snow pack above 15mph (4L below). 4A for intermittent snow pack, rain, hard dirt/gravel. In other words 4H when you know there will be wheel slippage, 4A when you're not sure.

At order time i kinda wanted 4A ( I had it on an old Explorer and it worked well) but couldn't get it on a non Sas BB. I'm kinda glad now because it seems to be a bit glitchy and I flat tow and that seems to be where problems arise.

 

[CactusBob]

Holy thread revival Batman Curious, for those that do NOT have 4A, what happens when you choose GOAT mode = Slippery? Guessing it engages 4H?

Slippery mode engages 4H.

 

[Scott R Nelson]

By traction gain I just mean that the front wheels engage when the computer decides adding to your traction and that is not something that can be really anticipated.

I still don't get it. What is that supposed to feel like to me as the driver?

I have never noticed when the front wheels engage or disengage. I think that it might show something on the display that shows what is and isn't engaged in off road mode, but I'm usually too busy paying attention to where I'm going to look there.

 

[Roach011]

I still don't get it. What is that supposed to feel like to me as the driver?

I have never noticed when the front wheels engage or disengage. I think that it might show something on the display that shows what is and isn't engaged in off road mode, but I'm usually too busy paying attention to where I'm going to look there.

I typically notice it when cornering. It feel like the front end is pulling the vehicle more than passively steering.

 

[userdude]

I still don't get it. What is that supposed to feel like to me as the driver?

I have never noticed when the front wheels engage or disengage. I think that it might show something on the display that shows what is and isn't engaged in off road mode, but I'm usually too busy paying attention to where I'm going to look there.

For me, I feel 4A more in the forwards and backwards movement of the Bronco. I used 2h the first couple weeks, then saw on here I could use 4A all the time and switched to it for like eight months. Then I took it in for service and they left it in 2H. I drove around for a week or so thinking the shocks or springs had a problem.

Then one day I switched it to 4A again and was like, ok, it feels more "level" starting and going over speed humps (my street has several). To test, the next weekend I went to 2H and again thought it was lurching backwards (?). I kinda felt like it made the truck feel weaker, if you will.

So I turned it back on, left it on unless maybe last November, then went back to 2H. Then I got used to 2H again and just recently (with some wet weather) turned 4A back on.

It's subtle enough you might not notice I guess, but I feel it's more planted in 4A for whatever reason. I cannot say in all those months in 4A and less in 2H I ever noticed it "shifting". 4A feels pretty consistent to me.

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