Another 4WD on pavement question

[ebelp]

How much more wear does leaving it in 4WD all winter actually do? I have never heard of this whole change it back and forth with any other vehicle - heck the Toyota FJ cruiser manual shift edition was a 4WD all the time vehicle. I put my vehicles into 4WD the first real snow and take it out in spring. Though I will admit in spring I do vary it - my driveway is usually a mess pretty late and hills vs. town are often drastically different driving conditions.

Is this a Jeep thing?

The manually literally says you will cause premature wear on the drivetrain if you leave it in 4HI and drive on dry pavement. This is the downside of a full-time 4HI transfer case setting, versus 4HI auto.

Sponsored

 

[johnnymiz]

try to minimize the angle of the turn that is on dry pavement... if it's a right turn, swing wide left on the snow as you come to the turn and angle to the right so you have to do less turning on the dry. that will reduce the binding. then, if it's a straight run, leave it in 4hi until you get up to speed an can lift off the gas to slide it into 2hi. 100 yards on a dry straight wont damage your truck. turning will, so minimize that and you're good.

 

[RockyMtnHigh]

This is why it wears.



4WD relies on the tires to slip, which they tend not to do on dry pavement.

 

[Foolish]

Rubicons are not an awd vehicle, so when you shift into 4 hi your in 4 wd all the time until you shift back into 2wd, the Sahara with selctrac is more like what your describing. They have the ability to go in and out of 4 wd as conditions dictate when 4 wd auto is selected.

I do know the difference between the two and the FJ Cruiser is 4WD.

Yeah it could be our winter roads are different - we don't get the wet pavement / melt that we got in Michigan winters. No one I know here takes their vehicle in and out of 4WD all winter.

 

[johnnymiz]

your FJ cruiser does not have the same type of transfer case as the Rubicon. the FJ has a limited slip differential built into the t-case allowing slip between the front and rear axles when on dry pavement. The Rubicon does NOT. So, when you go around a turn on dry pavement in the Rubi, the front axles travel a longer distance than the rear and the t-case binds up.
from toyota describing the 6sp full time 4x4 FJ t-case:
'With the manual transmission, the transfer case uses a TORSEN® limited-slip center differential for full-time 4WD with a locking feature. The differential distributes the engine’s power 40:60 under most driving conditions. The TORSEN unit varies power distribution as needed, based on steering angle and wheel slippage. In the Lock position, the differential switches to a 50:50 power distribution'
.

 

[johnnymiz]

i saw that, too. hhahah. prob gets covered in snow in sept and doesnt go to clean pavement til may. BRRRRRRRR

 

[crash13]

the FJ has a limited slip differential built into the t-case allowing slip between the front and rear axles when on dry pavement. The Rubicon does NOT.

Good point, I was focused on the differentials and couldn't understand where binding was coming from if they weren't locked. Folow up question, why did they not build LSD into our Rubicon's transfer case? (i'm guessing something to do with off-road performance..)

 

[johnnymiz]

the sahara has the option of that kind of transfer case.
the rubicon does not
you were thinking axle diff locks. but they arent the same. believe me, if you had your axle diffs locked, the binding would be epic and you would either feel slamming as the tires lost and regained grip or you would blow a pumpkin up.

 

[johnnymiz]

well, it all depends on the grip, doesnt it? ive run locked axles on the street and the barking/slamming is what i mentioned. but if your diffs arent up to it and the grip its too good, you can blow them up.
if you look back in the thread, or in other threads on the subject, youll see that im not one of the doomsday guys.
i told the op that he can make his turn in 4wd, just try to lessen the angle of the turn to minimize the binding.
but if you push it on dry, good pavement with fat sticky rubber and locked diffs, you can, indeed ruin a diff.
and ive seen my sisters suburban tcase blow up because my nephew forgot to take it out of 4wd when the roads cleared and turned tightly into a parking space in the school lot.

 

[johnnymiz]

the automatic FJ is part time. the 6 speed manual is full time

 

[johnnymiz]

Hahahah. I'm with you there brother.
Im sure he wasnt being kind to it when he grenaded it.
And really, no offense was taken. I respect you experience.
As for your axle comments... I totally agree. Unless you do something stupid, it is REALLY hard to blow up an axle or tcase in normal use/abuse. But people unknowingly do stupid shit...like my nephew.when it bound up he shouldve stopped and backed off....instead, he pulled the wheel tighter and gave it gas. If he had backed off, all wouldve been good. Instead, he was a dumbass in front of his friends.
So, i was just stating what could happen if you really went too far. In practice, Ive driven Subs, jeeps, fj40s, scouts on pavement that alternated between snowy and dry and left them in 4wd to no ill effects. I just used some common sense, kept them as straight as possible on the dry, and if i had to cut a tight turn, slipped them in 2wd. Its all about common sense with a tcase that doesnt have a built in diff like an fj cruiser.

 

[crash13]

the sahara has the option of that kind of transfer case.
the rubicon does not
you were thinking axle diff locks. but they arent the same. believe me, if you had your axle diffs locked, the binding would be epic and you would either feel slamming as the tires lost and regained grip or you would blow a pumpkin up.

OKay, I think I get it also. Couldn't figure out why there would be binding in 4H, although I have experienced it myself!, since the diffs were still open. Then re-read the manual and watched the Roc-Trac video.
"In the event that additional traction is required, the transfer case 4H and 4L positions can be used to lock the front and rear driveshafts together, forcing the front and rear wheels to rotate at the same speed. The 4H and 4L positions are intended for loose, slippery road surfaces only and not intended for normal driving. Driving in the 4H and 4L positions on hard-surfaced roads will cause increased tire wear and damage to the driveline components.

The part I was missing is underlined. The driveshafts are locked together which means when turning in 4H or 4L, the front axle travels further than the rear, even with the diffs open. Way worse with diffs locked!

 

[johnnymiz]

CORRECT! Now you got it.
Keep in mind, the manual is being cautious to avoid prolonged abuse.
But as Sean K said, and i agree, short bits on pavement wont do real damage as long as youre not crankin on the wheel making a sharp turn.

 

[johnnymiz]

Sorry..typing on my phone and lost track. It was Folish from alaska who has the fj.
Im with it now ;-)

 

[Swanny297]

I have a Rubi and on my daily commute, there is a stop sign controlled side street that is uphill and has snow on it (these days) right before the intersection with the busy main road. I need 4H to timely pull out into traffic. Problem is that the main road is often clear of snow. I try to shift quickly back into 2H once I am moving, but occasionally, I hear/feel the front wheels bind as I am making the turn. How much extra wear am I really causing in that scenario?

Why are you worried about shifting back quickly into 2wd - make the intersection, gain a bit of speed lift your foot of accelerator and shift back into 2H

Sponsored