When to use 4WD high?

On dry pavement, this will cause binding on the gears, and can lead to transfer case failure.
Not true or every rock crawler would be broken. The black rubber on every rock crawling trail is proof driving in 4WD on high traction surfaces is not going to break yer Jeep, might wear down the tires but yer Jeep is tough enough to not break.... if everything is maintained.
 
"You should never travel in four-wheel drive on flat, smooth, dry roads, as it will damage your drivetrain."
You can find anything on the internet. I hear some humans are sexless too. That is why we have forums where guys with 40 years of 4WD experience can debunk the myths.
 
High speed handling, ie evassive maneuvers, will be compromized in 4WD with a locked center differential. There will be no mechanical issues but you could end up in a bad situation if an emergency arises. Of course the easy way to avoid any accident is looking far enough down the road to predict an emergency.
 
Hmmm after reading this thread I ran out to my TJ and engaged 4WD.......had no idea I could just leave it there in all conditions.

Damn owners manual anyway.
 
Note that the manual reads that one should not use 4H on dry pavement, whereas for 4L the manufacturer is more adamant, instructing that we do not exceed 25 mph in low range. Words have meaning and it must be presumed that the manufacturer intended a particular choice of words when it published it's comprehensive owners manual.

I'm not arguing about anything and words do have meaning.

I do wonder why the manufacturer states do not exceed 25 mph in low range when the NV231 has a 2.72:1 Low range ratio and the NV241 has a 4:1 Low range. There's a pretty big difference between the two.
 
yep, with my Rubi I doubt it'll go that fast. But my YJ with 3.07s would run 60mph in 4LO.
For fun, I ran my numbers through Grimmjeeper.

4:1/nv3550/33s/4.88/1st gear = 0.86mph @ 750rpm

4:1/nv3550/33s/4.88/5th gear = 25.96mph @ 4000rpm
 
During my 55 years of driving jeeps I have observed this:
In my shorter, much shorter time on the internet almost wholly based around the driving, wheeling, and modifying of the Jeep TJ et al, I have noticed that folks will repeat confirmation bias far more than anything truthful or anything that dispels any mythology or commonly accepted belief however wrong it is. They will also inherently dig in and make any statement that supports that position with no regard to veracity as long as it falls in line with the mistaken belief. Terrifies me sometimes.

Oddly, or maybe not so oddly, this forum is one of the few, very few places I've run across that has the least amount of that I've encountered. It still pops up from time to time, but by and large, when a truth is presented, once it has been explained, it is generally accepted. I have practically given up posting on a lot of forums because I have to keep repeating the same arguments over and over and it just never seems to sink in.

The flip side of that is I do understand that we should believe in the owner's manual. We should not however, take it as gospel on blind faith if there is some aspect of that may be written for other reasons. Face value may not be the whole story and there are often very different things that can be acceptable when practical application reveals a different result than the theory.
 
I do understand that we should believe in the owner's manual. We should not however, take it as gospel
Yes, a certain amount of the Manual is written to avoid liability and reduce warranty claims. That said, for a "trouble free" TJ, yes, take it as gospel. But there are many things you can do beyond the Manual with a bit of common sense or mechanical acumen. And there will be times you need to bend the rules... or walk. The value of these forums, even for old farts like me with 40 years of 4x4'ng, is learning what can be done and what to avoid. I learn something new every year.
 
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. . . I do understand that we should believe in the owner's manual. We should not however, take it as gospel on blind faith if there is some aspect of that may be written for other reasons. Face value may not be the whole story and there are often very different things that can be acceptable when practical application reveals a different result than the theory.

Which is why I said "follow the owner's manual whenever possible and use common sense." Perhaps I should have said "follow the manual whenever possible but use common sense." Following the manual is the safest course of action but may not always be possible, practicable or even desirable in some situations. That's where common sense and some mechanical knowledge comes in.
 
Yes, you can grenade front differentials and transfer cases putting it into 4hi on the street. The wife did both. In the Suburban with a high output 454. Bang. Oil and shrapnel on the pavement. Took her three tries though with that POS GM pushbutton automagic system. It was very expensive to teach her to use four wheel drive in that rig. Probably had something to do with North of 400 HP and North of 500 ft-lbs torque.

The TJ transfer case is relatively more robust. No issues yet with her JKU, or my TJ. They (the front tires) sometimes complain a little, but nothing has broken yet. My opinion is you'd have to really work hard to kill the Jeep transfer case and front differentials.