Topic: 4H on the highway?

[jfrabat]

So what could theoretically happen if a person were to run his/her Jeep on 4H on the highway for, say for 22 miles (some on roads, others at highway speeds)?  Of course, this is just a theoretical question...  OBVIOUSLY I would not do something like that!   

[grumpygy]

Not much would be my guess.  Have done it longer than that in snow.

[chardrc]

depends on how much turning you do. if its fairly straight you should be ok but keep it to a minimum. I know someone who forgot to take their truck out of 4hi a twice coming back from hunting trips and went 200 miles + in 4 hi  transfer case is still going after 130k miles but it did puke out some fluid the first time from getting hot (said driver changed the fluid shortly after). of course this was on a 3/4 ton truck not a jeep but its the same basics. just puts more load on the t-case since the axles are geared so the front pulls a little more than the rear so you are slightly dragging the rear. then there is the binding when turning.

[jfrabat]

depends on how much turning you do. if its fairly straight you should be ok but keep it to a minimum. I know someone who forgot to take their truck out of 4hi a twice coming back from hunting trips and went 200 miles + in 4 hi  transfer case is still going after 130k miles but it did puke out some fluid the first time from getting hot (said driver changed the fluid shortly after). 

Would this driver be some fellow 4banger member?   

then there is the binding when turning.

Yeah, that's how I noticed I was in 4H (I mean, in the hypothetical scenario, of course).

I think I am OK (I used the Jeep the day after, and ran it in 4H and 4L one some dirt roads going to some land I bought, and it ran fine), but wanted to check just in case...

[jagular7]

Keeping the jeep in 4hi links the front and rear ds together through the chain in the 231. If its an open diff front and rear and with a road that has the capability to provide slip of the tire, there shouldn't be an issue.
Its about the binding of the driveline to the friction/contact of the tire maintaining that binding. Jeeps hop, skirt, etc on the rocks in Moab, but mind you they are off-idle.

If it was my vehicle, I wouldn't need 4hi at any speed on the street. I would maintain an acceptable speed in 2hi. I've never used 4hi constantly on the street. I use it to get going up my hill and driveway. Otherwise, I'm 2hi all the time.

[VA_YJ]

I think the scenario Felipe is describing is when someone (not him) is offroading in 4wd and forgets to shift back into 2wd.  Someone I know did this after driving on the beach with a Jeep that has open diffs and after 15 miles on the pavement, the person (not me of course) realized the error and shifted into 2wd.  I (I mean the person) did not noticed any problems, but it certainly does put a strain on the transfer.  Bottom line - if it ain't broke, don't fix it.

[Tr00b]

I had a similar incident... Never saw any ill effects. They made trucks back in the day that were full time 4wd aka NP203 cases... They seemed to survive everything except passing a gas station.

[Jeffy]

I had a similar incident... Never saw any ill effects. They made trucks back in the day that were full time 4wd aka NP203 cases... They seemed to survive everything except passing a gas station.

The NP203 has a central differential.

[jfrabat]

VA_YJ is right, that is exactly what I was asking (in a hypothetical case, of course, as I would not be dumb enough to do it, OBVIOUSLY!).  So far (in the hypothetical case!), I have not seen any ill effects.  In reality, i did not even notice until I turned into my driveway (hypothetically speaking).

[Jeffy]

VA_YJ is right, that is exactly what I was asking (in a hypothetical case, of course, as I would not be dumb enough to do it, OBVIOUSLY!).  So far (in the hypothetical case!), I have not seen any ill effects.  In reality, i did not even notice until I turned into my driveway (hypothetically speaking).

It can cause excessive drivetrain bind.  If the tires aren't able to release the binding then the drivetrain has to.  This usually means you get some twisting action at the axle shafts on the D30. I wouldn't make it a habit.  Short term, it shouldn't be that bad.  But it's like bending a clothes hanger.  Eventually it will break.  15 miles isn't a big deal.  The other problem was heat build up.

[jagular7]

You should be feeling and noticing the binding action. First thing to do is off the gas, straighten out steering as soon as possible, and coast. Once going straight, reach down and push into 2hi. Wait a few before applying the gas. Then just continue on.
If you bind enough, something will bend, shear, crack, etc. You either notice that damage there, soon, or later on the trail.

[dwtaylorpdx]

I find that the binding at speed is worse on the straights, tha action of turning allows the binding to release.. That being said I've done literally thousands of miles in 4hi on the highway,, My YJ has 220K on it and the Tcase is the ONLY part of the drive train that has never been opened up..

I have a hub kit and no axle disconnect.. :)

My Previous Toyota 4x4 pickup recieved teh same treatment for 250K miles..

Ittle live..

Dave