Driving with 4x4 high on highway

m3reno

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Went to Smith Point today driving on the beach!! Aired down to 17 lbs and the keep was flawless.......BUT after airing up and driving about 60 to 70 mph on the highway I realized I forgot to take it out of four wheel high. My question is, do you think I did any damage? Should I change the diffs oil?





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Dan M.

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Probably no damage. I believe you are more likely to do damage at low speeds with tight turns as the outside wheel will have to spin much faster than the inside wheel during tight turns which can cause binding. At highway speeds you are for the most part going straight. I believe if you caused damage you would know (wheel hop, terrible noises, etc). Please note, I am not a mechanic so I could be off base. This is just what I have read on threads and what I researched when deciding on the 4 wheel drive system I was going to get. Hopes this helps
 

oceanblue2019

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Went to Smith Point today driving on the beach!! Aired down to 17 lbs and the keep was flawless.......BUT after airing up and driving about 60 to 70 mph on the highway I realized I forgot to take it out of four wheel high. My question is, do you think I did any damage? Should I change the diffs oil?
You'll be fine unless you were doing figure 8's down the highway ;)
 

mgroeger

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Did the same thing about 30,000 miles ago and have had no I'll effects. Just don't do it again... lol.
 
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m3reno

m3reno

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I feel much better. I think I will change the oil as a precaution. I went a total of 35 miles on the highway. The weird thing is I didn’t feel any binding until I came to the restaurant and slapped both hands on my head!!
 

Spank

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I feel much better. I think I will change the oil as a precaution. I went a total of 35 miles on the highway. The weird thing is I didn’t feel any binding until I came to the restaurant and slapped both hands on my head!!
It's the sharper turns that you gotta worry about, which aren't gonna be on a highway. You probably put more stress on the diffs when you made the turns onto and off the ramps, but your Jeep'll be fine.
 

chacomaya

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Been there, too. I imagine that any extra stress that might have been caused was not so much to the diffs as to the transfer case, since the diffs are open unless you lock them.
 

SpeedKills

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I feel much better. I think I will change the oil as a precaution. I went a total of 35 miles on the highway. The weird thing is I didn’t feel any binding until I came to the restaurant and slapped both hands on my head!!
There's probably no reason to change the engine oil early. If you're worried you can drain and refill the diffs and transfer case, but it's probably not necessary either.
 

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Been there, too. I imagine that any extra stress that might have been caused was not so much to the diffs as to the transfer case, since the diffs are open unless you lock them.
This exactly. If you were going to experience any problem, it would almost certainly be to the transfer case and you would know it. If you don't see gears and fluid leaking, you are fine. A fluid change won't make any difference since the transfer case gears turn all of the time anyway. The only thing that would have had any extra "wear" would be the front diff and this one short trip wouldn't give close to excessive wear.
 

wolf

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One year I returned from a tour of duty in Munich,Germany picked up my 1979 Golden Eagle CJ7 at Bayonne N J. Hooked a 8 foot u-haul loaded to the CJ and headed for Co. A wife 2 kids, 14 suitcases and a motorcycle. It was loaded. Heading west out of PA on the worst interstate road I have ever experienced. Well, ran into ICE, Snow almost all the way to Colorado. I used 4 wheel high most of the time. Sometimes I hit dry roads for a while but kept it in 4wheel high most of the time. Straight stick transmission and straight 6 engine(258ci). Never a problem. Drove that jeep for many years and never a problem. Steering and ride was great. So I think like was mentioned above mostly straight interstate and no sharp turns etc. don’t think you will have a problem.
 

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I believe the owners manual says you can drive in 4H up to 55 or 60 MPH.
 
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m3reno

m3reno

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Thanks guys!! As I get older I have to start leaving post it notes all over!!
 

D60

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Only a few here understand how the system works. The diffs couldn't care less - ring and pinions are meant to see constant loads and the front doesn't care what the rear is doing and vice versa.

The theoretical danger is to the CHAIN in the t-case as it is what connects front and rear outputs together and can be subject to stretch. However, we're not talking bike chains or even timing chains - the t-case chain is heavy duty and huge. Now manufacturers do size t-case chains according to GVWR and HP, as is the case with GM NP261 (mostly 1/2T gassers), 261HD (3/4T) and 261XD (mostly Dmax's), so I don't know exactly how big the chain is in the JL 'cases but as a rule they err on the side of overkill.

In a part-time system the chain does not spin all the time -- only when 4hi or 4lo is called for.

So, what if you manage to stretch your chain? Typically, you won't know or care unless it's REALLY bad, at which point it might sag enough to wear thru the case (highly unlikely), or you might hear chain slap (remember, only in 4wd as the chain is idle in 2hi), or it MIGHT slip under SEVERE load in 4wd (again, very unlikely).

You'd have to drive across an entire Western state in 4hi on pavement (not those little east coast states that are the size of our counties) to do significant damage IMO.

So, worry not, return to COVID fears, and have a Coke and a smile ;)
 
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m3reno

m3reno

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Only a few here understand how the system works. The diffs couldn't care less - ring and pinions are meant to see constant loads and the front doesn't care what the rear is doing and vice versa.

The theoretical danger is to the CHAIN in the t-case as it is what connects front and rear outputs together and can be subject to stretch. However, we're not talking bike chains or even timing chains - the t-case chain is heavy duty and huge. Now manufacturers do size t-case chains according to GVWR and HP, as is the case with GM NP261 (mostly 1/2T gassers), 261HD (3/4T) and 261XD (mostly Dmax's), so I don't know exactly how big the chain is in the JL 'cases but as a rule they err on the side of overkill.

In a part-time system the chain does not spin all the time -- only when 4hi or 4lo is called for.

So, what if you manage to stretch your chain? Typically, you won't know or care unless it's REALLY bad, at which point it might sag enough to wear thru the case (highly unlikely), or you might hear chain slap (remember, only in 4wd as the chain is idle in 2hi), or it MIGHT slip under SEVERE load in 4wd (again, very unlikely).

You'd have to drive across an entire Western state in 4hi on pavement (not those little east coast states that are the size of our counties) to do significant damage IMO.

So, worry not, return to COVID fears, and have a Coke and a smile ;)

LOL, yes we must all return to covid fears!! Funny thing is I was working in Manhattan on a construction project on the onset of covid and am now in the Bronx and Queens. My cousins stayed away from me because I was in the so called HOT ZONE!! Fast forward to today I found out that my cousins had a party for his sons high school graduation in late June and it turned out his son had covid and spread it to all of the family members!! No body died, thank God, but he calls me every week to come by and visit and NOW I'm the one saying that his house is a HOT ZONE!!
 

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