Looking for shortcuts and quick tips on shifting transfer case while off-roading

[Kaptainkid1]

After year of owning my TJ I wanted to know a little facts about the transfer case shifting procedures. I've owned other modern 4x4 and I wanted to know the ability of NV231 case shifting.

I had a Nissan Pathfinder and I can shift from 2wd high to 4wd high up to 25 mph. I can also shift back to 2wd I believe it was shift on the fly.

Can the Jeep TJ shift on the fly from 2wd to 4wd and back while moving? I was told no by the last owner and I would have to stop and back up a few feet before going forward to engage into 2wd hi.

Also shifting from 4wd high to 4wd Low. I was told only need to stop. Then it's in gear. Shift back from 4wd low to 4wd high just stop and can proceed forward.

I feeling I was told backing up was unnecessarily is this method correct?

Can the NV231 be shift on the fly or some version of the fly shifting?

I have a manual 5 speed and not an automatic. So I feel that transmission might have more flexibility then the auto version.
Can someone enlighten me?

 

[Wildman]

As far as shifting on the fly from 2hi to 4hi yes you can. I would shift into 4hi doing 55-65 MPH when driving in the snow. Now shifting from 4hi to 4lo you have to come to a complete stop or be going slower than 2 MPH.

 

[Steel City 06]

Unlike most more modern cars, the TJ does not have automatic (or even manual) locking wheel hubs in the front axle.

If you were to tear apart a different vehicle, say a YJ, a Pathfinder, or an F150, you would find automatic vacuum locking hubs in the front axle. These disengage when the car is in 2WD, so the front driveshaft and front differential don't spin at all. This disconnect results in slightly better fuel economy and less noise and vibration.

In one of those vehicles, if you shift into 4WD at speed, that front drivetrain must be brought up to road speed somehow. Either the hubs or the transfer case must engage it and slip until it is at the correct speed. This causes significant noise (often grinding) and results in wear over time. So most manufacturers won't recommend that you engage 4WD at high speeds.

The TJ and JK, however, do not have locking hubs. They are permanently engaged. Thus the front drivetrain is always spinning at speed. When driving in a straight line, it is spinning at the same speed as the rear. The gears in the transfer case are already spinning at the same speed. Thus, if you engage 4WD at any speed in a straight line, there will be no grinding. You can safely go into 4WD at any legal speed. You can generally shift under power as well as long as there is no wheel slippage at the time of the shift.


Going into 4LOW is a little different. Because you are changing ratios, the transmission has to be brought to the new increased speed of the transfer case. So shifting at any significant speed is likely to cause grinding. So it is generally recommended to be in neutral and moving very slowly or stopped to shift. Often, when stopped, the teeth line up just wrong and the transfer case won't go into gear. Either roll the car slightly or put the TC back into neutral and use 1st gear and let out the clutch for a second or so to rotate the transmission. Keep trying until the teeth line up.

Theoretically, you could shift between 4LOW/4HI at speed by treating it like an unsychronized manual transmission with no clutch. If you could time the shift perfectly and rev match it, you could theoretically shift with no grinding at any speed. I have yet to see shifting skills that good.

 

[Goatman]

I would never try and shift a 4wd transfer between hi and lo range at anything other than a snail's crawl. AWD is a completely different transfer case design, and people often think they are the same. The TJ transfer is basically unchanged in design from the original WWII designs and 50's designs. Be very careful moving between hi 2 and 4. Ideally at coasting (but in rpm range) so there is easier engagement. Can you do things differently? Absolutely. Can it cause a problem? Absolutely.
Shifting from hi to lo at speed would be like shifting the transmission from 5th on the highway directly to 1st.

 

[jjvw]

The transfer case won't let you shift into 4low at anything other than a slow speed. There's no recommendation to do otherwise unless you aren't bothered by grinding gears.

 

[Kaptainkid1]

4wd hi to 2wd hi it is not necessary to stop and go in reverse then forward then? That was just misinformation?

 

[Wildman]

4wd hi to 2wd hi it is not necessary to stop and go in reverse then forward then? That was just misinformation?

This was back when you had automatic hubs on a vehicle. My Nissan hardbody p/u had them. So NO you do not need to back up after you take your TJ out of 4wd.

 

[jjvw]

4wd hi to 2wd hi it is not necessary to stop and go in reverse then forward then? That was just misinformation?

Misinformation. I've done it at 75mph without stopping.

 

[Wildman]

Misinformation. I've done it at 75mph without stopping.

It isn't misinformation it is just being applied to the wrong vehicles. He said he use to have a Pathfinder and I'll bet they still used the auto hubs on them. To unlock them you had to stop and back up.

 

[jjvw]

It isn't misinformation it is just being applied to the wrong vehicles. He said he use to have a Pathfinder and I'll bet they still used the auto hubs on them. To unlock them you had to stop and back up.

Our TJ hubs are always engaged. Why would locking or auto hubs make a difference?

Edit!

Because if the front drive shaft and diff isn't spinning when 4wd is engaged, bad things would happen.

The reason is specifically because the TJ hubs are always engaged.

 

[pagrey]

I think @Wildman means because auto locking hubs need to turn backwards to unlock. That's the whole stop and go backwards part going from 4wd to 2wd. It has nothing to do with the driveshafts.

 

[onoffroad]

With all this said, sometimes you may have to backup a bit to get out of 4 lo. Especially if you are driving on harder ground where there isn't a lot of slippage(gravel roads,steep hard pack and such) . Because of the stresses that build up in the system. Or if 4wd hasn't been used in a while.

 

[jjvw]

I think @Wildman means because auto locking hubs need to turn backwards to unlock. That's the whole stop and go backwards part going from 4wd to 2wd. It has nothing to do with the driveshafts.

I'll create the pointless scenario of engaging 4wd at highway speeds with the hubs unlocked. Bad things would happen if the driveshaft isn't up to speed with the back half of the transfer case.

Dropping out of 4wd at highway speeds would be different. If the hubs are locked, it would behave like a TJ. If the hubs auto unlock at highway speeds and can't disengage unless rolled backwards, wouldn't they just stay engaged until they find the opportunity to fully unlock?

 

[jjvw]

With all this said, sometimes you may have to backup a bit to get out of 4 lo. Especially if you are driving on harder ground where there isn't a lot of slippage(gravel roads,steep hard pack and such) . Because of the stresses that build up in the system. Or if 4wd hasn't been used in a while.

When? It's been 7 years and I've never once needed to back my TJ up to get out of 4 low.

 

[Cedar128]

After year of owning my TJ I wanted to know a little facts about the transfer case shifting procedures. I've owned other modern 4x4 and I wanted to know the ability of NV231 case shifting.

I had a Nissan Pathfinder and I can shift from 2wd high to 4wd high up to 25 mph. I can also shift back to 2wd I believe it was shift on the fly.

Can the Jeep TJ shift on the fly from 2wd to 4wd and back while moving? I was told no by the last owner and I would have to stop and back up a few feet before going forward to engage into 2wd hi.

Also shifting from 4wd high to 4wd Low. I was told only need to stop. Then it's in gear. Shift back from 4wd low to 4wd high just stop and can proceed forward.

I feeling I was told backing up was unnecessarily is this method correct?

Can the NV231 be shift on the fly or some version of the fly shifting?

I have a manual 5 speed and not an automatic. So I feel that transmission might have more flexibility then the auto version.
Can someone enlighten me?

Per Chrysler on my 2001 Sport.....

 

[pagrey]

When? It's been 7 years and I've never once needed to back my TJ up to get out of 4 low.

Sorry neither of us must have been clear. The reason that somebody suggested stopping and driving backwards to disengage 4wd is from other vehicles that have auto hubs, not our Jeeps. We were just observing where the advice came from, not saying it is necessary on our Jeeps at all.

 

[jjvw]

Sorry neither of us must have been clear. The reason that somebody suggested stopping and driving backwards to disengage 4wd is from other vehicles that have auto hubs, not our Jeeps. We were just observing where the advice came from, not saying it is necessary on our Jeeps at all.

The claim gets made for our TJs quite often.

 

[Zorba]

Another question: Rolling at snails pace, shifting into 4-low. Main transmission in gear? Neutral? Clutch engaged or not?

 

[jjvw]

Another question: Rolling at snails pace, shifting into 4-low. Main transmission in gear? Neutral? Clutch engaged or not?

Not necessary. Easier if you do. I do.

 

[Jerry Bransford]

Dead slow, slower than a snail's pace. Any slower you'd be stopped.