Can you engage 4 LO from a standstill?

[CybrSlydr]

So, I went back out to AEP with my brother today to do some fishing (didn't fish any, all the ponds are too full of green and icky) and got to drive around a bit. Not very serious off-roading, but it was still fun as hell. Before we left, I thought I should familiarize myself with how the 4WD system works, so I got the manual out.

The manual stated to get into 4LO I should be moving forward at about 2-3mph, put the transmission in Neutral and then smoothly crank the handle up into 4LO while coasting forward (this didn't work at first because I failed to recognize on the handle the illustration to move to the right when in 4HI and then up and towards me to put it in 4LO - I kept hitting the stop at 4HI and gave up before I was afraid to break something - lol).

Can you still engage the 4LO from a stand-still once the vehicle is started and in Park?

 

[jjvw]

If the splines between 4lo and 4hi are lined up then you can shift while at a stand still. I've done it. Chances aren't good of that happening, which is why the t case needs to be rolling in order to get the two different gear ratios to line up.

2003 Rubicon

 

[JMT]

I’ve had good luck going from 2WD to 4LO at a standstill. When I go from 4HI to 4LO at 2-3 mph, like the manual says, it sometimes works and other times doesn’t sound very appealing, so I usually stop. BTW, you can shift from 2WD to 4HI up to around 40mph, and I’ve done this many times, as smooth as silk

 

[CybrSlydr]

If the splines between 4lo and 4hi are lined up then you can shift while at a stand still. I've done it. Chances aren't good of that happening, which is why the t case needs to be rolling in order to get the two different gear ratios to line up.

2003 Rubicon

So 4LO is used proactively to keep you from getting stuck rather than as a, "Well, I'm stuck, what do I do now"? My mind always thought of it as like... First you try 4HI, then if you get stuck there, you go to 4LO - if you have to be moving for the splines to match up, then you better be in 4LO before you get to the part where you might get stuck, else you're boned without a winch.

 

[jjvw]

So 4LO is used proactively to keep you from getting stuck rather than as a, "Well, I'm stuck, what do I do now"? My mind always thought of it as like... First you try 4HI, then if you get stuck there, you go to 4LO - if you have to be moving for the splines to match up, then you better be in 4LO before you get to the part where you might get stuck, else you're boned without a winch.

I suppose so. I do enough trails where 4L is just the way it is much of the time. 4L is usually easier to get into while stuck than getting the lockers to engage.

2003 Rubicon

 

[JMT]

X2. I rock crawl, so I’m all the time in 4LO. It’s the name of the game, go slow

 

[jjvw]

... BTW, you can shift from 2WD to 4HI up to around 40mph, and I’ve done this many times, as smooth as silk

I recall the manual saying you can shift from 2H into 4H and back up to 55mph. I've done it at 80. The gearing is the same, so everything should line up at any speed. Not that you should...

2003 Rubicon

 

[JMT]

I recall the manual saying you can shift from 2H into 4H and back up to 55mph. I've done it at 80. The gearing is the same, so everything should line up at any speed. Not that you should...

2003 Rubicon

You’re TJ will go 80? I coudn’t remember the exact speed.

 

[jjvw]

You’re TJ will go 80? I coudn’t remember the exact speed.

Eventually. I've gotten it up to 90 once before I regeared.

2003 Rubicon

 

[glwood]

Why would you want to shift from 2HI to 4HI at 80?

Why would you want to go 80 period?

 

[jjvw]

Why would you want to shift from 2HI to 4HI at 80?

Curiosity. I've forgotten to shift out of 4h many times before hitting highway speeds. I've never slowed down for that and the action was smooth and completely uneventful.

If you actually need to be in 4h while on pavement, then you absolutely should not be going 80. That would be unsafe.

...

Why would you want to go 80 period?

Wyoming, Texas, Utah...

2003 Rubicon

 

[jeep_boss]

Why would you want to shift from 2HI to 4HI at 80?

Why would you want to go 80 period?

80mph is my personal maximum operating speed for my Jeep. If the tires are rated for it, why not?

 

[jeep_boss]

So, I went back out to AEP with my brother today to do some fishing (didn't fish any, all the ponds are too full of green and icky) and got to drive around a bit. Not very serious off-roading, but it was still fun as hell. Before we left, I thought I should familiarize myself with how the 4WD system works, so I got the manual out.

The manual stated to get into 4LO I should be moving forward at about 2-3mph, put the transmission in Neutral and then smoothly crank the handle up into 4LO while coasting forward (this didn't work at first because I failed to recognize on the handle the illustration to move to the right when in 4HI and then up and towards me to put it in 4LO - I kept hitting the stop at 4HI and gave up before I was afraid to break something - lol).

Can you still engage the 4LO from a stand-still once the vehicle is started and in Park?

My Jeep is finicky with 4Lo, unless I put my Jeep in neutral first then shift into 4Lo - otherwise it grinds.

I can handle engaging it from a stand still like that, but what i do not like about it (with my 5.13 gearing and 6spd manual) is that my Jeep lurches forward no matter how soft I pop my clutch.

 

[tquig01]

So, I went back out to AEP with my brother today to do some fishing (didn't fish any, all the ponds are too full of green and icky)

Starting by saying I am envious- our ponds are still frozen!

Can you still engage the 4LO from a stand-still once the vehicle is started and in Park?

If everything is lined up , i.e. all the splines in the T-case, then yes, but it is best not to force it. You could end up bending the transfer case lever enough to knock it out of adjustment. Best just to have it running and moving slightly to keep things happy.

 

[Jerry Bransford]

Understand that 4Hi in our transfer case is synchronized, 4Lo is not. You can shift in/out of 4Hi at any safe speed. The gears for 4Lo may not be aligned with each other so if you're stopped, they may not mesh so they'll grind when you try to shift into 4Lo if you are completely stopped. As the owner's manual recommends and recommendations made above said, simply make it a habit to be rolling/moving at a dead slow crawl, like at 1-3 mph, before pulling the lever into 4Lo. That is the correct and recommended way to shift into 4Lo. Shifting into 4Lo when completely stopped is simply likely to produce grinding.

 

[xackley]

With my manual transmission I put it in neutral, at a dead stop, push in the clutch and pull the lever all the way. I must admit I have only done this about four dozen times, but without a problem and with zero grind.

 

[Jerry Bransford]

With my manual transmission I put it in neutral, at a dead stop, push in the clutch and pull the lever all the way. I must admit I have only done this about four dozen times, but without a problem and with zero grind.

Jeep must have let one tcase slip out of the factory with a synchronized 4Lo.

 

[WWII Jeeper]

Curiosity. I've forgotten to shift out of 4h many times before hitting highway speeds. I've never slowed down for that and the action was smooth and completely uneventful.

If you actually need to be in 4h while on pavement, then you absolutely should not be going 80. That would be unsafe.




Wyoming, Texas, Utah...

2003 Rubicon

Done that a few times, thru Wyoming, Utah, and Nevada where you get those snowy, icy stretches of I-80, and when the pavement gets somewhat dry.....you just plain forget about 4wd..... never had a problem or odd noises, other than a lack of coffee.....

 

[Tristar_tj]

Glad I found this post ... I recently tried to engage my 4LO in my 06 TJ automatic and did NOT succeed
I tried at a stop at first then at a roll, about 3-5 mph. I will try a slower roll next time. Is it possible to turn the engine off, place trans in neutral then try and engage 4LO?

 

[Jerry Bransford]

Glad I found this post ... I recently tried to engage my 4LO in my 06 TJ automatic and did NOT succeed
I tried at a stop at first then at a roll, about 3-5 mph. I will try a slower roll next time. Is it possible to turn the engine off, place trans in neutral then try and engage 4LO?

Engine running, shift to Neutral, then be rolling at a DEAD-slow crawl and it will pull right in.