When shifting to 4L, my front wheels are not driven. Shifting to 4H works fine, but it takes luck and several attempts and maybe some driving around in 4H before they are eventually driven.

This can get me into trouble, and I'd like to do something about it. But I've no idea how engaging the front wheels works. It appears as if there's some electically controlled device sitting on the front diff that might be used to lock something in the diff or so. That wouldn't explain why 4H works and 4L does not, though.

Maybe it's only a broken wire or a bad contact somewhere ...

Can anyone shed a light on this?

i dont know much about the factory system, but i told myself when my 4 wheel quits working im gonna replace it with the 4x4 posilock system. $150 and you wont have problems again. you also get 2low.

That sounds interesting :) Do you mean that one: http://www.eastcoastoffroad.com/posi/#kseries

Seems that it is a mechanically controlled system :)

Well, from their description of the OEM system, it appears that after shifting to 4L, I need to turn the front axle for a while until sufficient current has been generated to heat up the plunger enough so that it locks. Did I understand that right?

This would match the behaviour I'm seeing. I'm turning off the engine to switch into 4L, otherwise I get stuck in N or cannot shift at all. Then it will take some load on the drivetrain to generate the heat, but I don't get enough heat because I'm driving too carefully.

But if that is true, what happens when the plunger suddenly locks the diff under load? Won't that break the diff or so? And how comes that it works perfectly in 4H but not in 4L?

BTW, 2L is pretty useless --- that is what I'm usually getting when shifting to 4L. It is very hard on the rear end as you get too much torque on it, and the rear wheels just dig in quickly.

Are you going into 4L properly, you must be stopped and in N before PCM will attempt to engage 4L, 4H will engage while rolling, best thing to do is if you think you will need 4L go there before getting into the muck.

Steiner you have the newer actuator style, it should last a long time, early style were ones prone to not to engage.

PS:

The front wheels would disengage if the truck is not moving, wouldn't they?

TDoc,

to shift to 4L, I stop the truck, shut off the engine, shift to 4L and then restart the engine. I tried a couple of times to shift to 4L while moving, exactly as described in the manual, but I'm grinding the gears MOTT and get stuck in N. I couldn't get out of N with the engine running; N and 4L are not synchronized.

How do you exactly shift into 4L?

Mine grinds as it engages in N but that's it and it's engaged after that.

my instructions say to engage 4L in N only while stopped, if I don't do it that way the 4L indicator blinks and won't engage 4L, maybe a little different with OBD II vs OBDI although your 96 should be OBDII when reading codes do you show 2 digit or 4 digit codes some 96 are mix of OBD-I or II depending which production run you have as they phased into OBD-II

PS:

The front wheels would disengage if the truck is not moving, wouldn't they?
They should, maybe your actuator is weak and rolling in 4H helps engage and not enough oomph to move while stopped and go into 4L<!-- / message --><!-- sig -->

Slow/sluggish engagemnet will usually go away with use. Pop it into 4hi at least once a month and it will stay functional. To help it out now, just engage/disengage whenever you get an excuse, even if you don't need it. It will loosen up. Same goes for 4LO to keep the tansfer case happy.

QM,

sorry, I should have pointed out that the N position I'm refering to was that of the transfer case, not the transmission. I can get the transfer case into N while moving without grinding, but then I'm stuck there. Once I managed to get through to 4L, but not without much grinding. I decided that I could damage the transfer transmission and never again tried to shift it into N or 4L while the engine was running after my very first attempts.

TDoc,

my owners manual says one should drive slowly (5--7 mph) and try not to accelerate or decelerate while shifting the transfer case. It says that one should not shift the transmission into N and that one must not stop the lever of the transfer case in neutral when shifting it. I've tried exactly that, but at the time I get the transfer case into N, the truck stops moving almost immediately so that I cannot get the lever through to 4L. The only way to get the transfer case out of N (in either direction) is turning off the engine :( --- Turning it off to get into 4L and out of it won't be a nice solution, but I could live with it if it only would work.

Told from the plug, I've ODB-II, but I'm not sure about the codes. I think there have been 3-digit ones when the vacuum pump failed.

The 4wd indicator never blinks. It always lights up when I shift into 4H or 4L, but that doesn't mean that the front wheels are driven. I guess it's just a rather meaningless light that comes on by a switch on the transfer case, though the manual says that it could stay on to indicate that 4wd is still active after harsh offroad use, until 4wd actually disengages.

Fingers,

4H engages immediately, it's only 4L that makes trouble. Thus, 4H is easy to use (though I should do it more often ...), but 4L is rather useless because I have to turn off the engine to get it in or out and because the front wheels don't get driven. They are not driven even if I shift from 4H to 4L, though they were driven in 4H just a moment before. This might indicate that something happens when I shift even when the engine is off.

Thus, if I need 4wd, I only can use 4H. If I shift to 4L and the front wheels aren't driven, the rear wheels just dig in quickly and it becomes hard to get out.


But I'd need 4L to get around in mud because the wheels are spinning too fast in 4H and it gets hard on the transmission. Then, 4L is required in sand --- there's not enough torque available in 4H to turn the wheels without taking risk of overheating the tranny: 1600 RPM in 4H and the wheels still not turning will probably kill it very soon ... I didn't dare to rev up more than that with the wheels stuck.

What are you supposed to do when you get stuck in sand in 4H? You cannot get out in 4H, but you cannot get 4L to drive the front wheels, so you'll need someone to tow you out.

Does it work for someone to turn off the engine, shift to 4L, start the engine again and have the front wheels driven then? Maybe the system doesn't work just because I turn the engine off.

to get in/out of 4lo you must put the transmission in N then shift directly from 4hi to 4lo without stopping in the transfer case N. There is usually a rather hard "clunk" but not bad. I am not sure what is going on with your front axle. I very well could be a misaligned switch on the transfer case shifter.

THX! Must the truck be stopped or moving when shifting the transfer case?

Going to 4H with transmission in N while not moving works fine, maybe it also does for 4L --- that would be great :)

THX! Must the truck be stopped or moving when shifting the transfer case?

Going to 4H with transmission in N while not moving works fine, maybe it also does for 4L --- that would be great :)
Start by being stopped, tranny in N and transfer case in gear. In one motion, try to go straight to 4 lo. If it will not go in, back off to 4 hi and then let the truck move very slowly while you try again. Remeber, don't stop at the neutral position on the transfer case.

Thanks again, I'll try that tomorrow :) I'll let you know what I find out.

i used to shift my old truck that way untill somebody told me how to do it the right way. i hated that awful sound it made when i stopped in neutral.

Olee,

the reason i want 2 low is for pavement.

Hm? Didn't Fingers describe the right way?

2L on pavement will tear the rear diff apart or something like that.

I've been reading a leaflet about the Nissan Patrol. It said that in 4L, you get about 2300 Nm _per wheel_. The engine provided only about 350 Nm. The 6.5 provides about 500 Nm, and gearing in 4L is probably about the same.

Thus, you may get 5000 or 6000 Nm or more to each wheel in 2L. If the diff and the grip of the tires would hold up to that, you could effortlessly turn your axle into a corkscrew and maybe sheer off the wheel bolts :) But the U-joints on the driveshaft would crack and the shaft would fall off long before, eventually cutting into the frame or so.

Somehow, I think that you do not want this ;)

PS:
Afair, 1 Nm means a force of 1 N (equals a weight of 100 grams) at the end of a lever that is one meter long. Thus, 6000 Nm mean 600kg (1481 lbs) pulling at a lever that is 1 meter (39 inches) long. --- Wheel nuts on 18 wheelers are tied to about 650 Nm. Mine are tied to 190, as the manual says they should, and that's pretty much already.

Does anyone have actual torque ratings the drivetrain can take?

The way I do it, (Don't know if its right) is 4H I dont do anything but let off the gas.

4L slow to almost stopped shift auto trans to N then quickly shift fron 2H or 4H to 4L.
I have found the quicker you shift the less noise it makes.
4L back to H range same way.
I used to back up a few feet after comming out of 4X4 but found this was a useless habit Left from my old truck.
it also seems to help to be barely rolling when going into low range not stopped. I have never killed the engine.
I use my 4x4 several times a week at the ranch so maybe mine is broken in.
Good Luck,
Justin

It works :)))

It becomes rather easy once you know how to do it and with some exercise. The lever on the transfer case seems to have a peculiar tendency to get into N instead of 4L, but it can be taken out of N without grinding the gears when the engine is turned off.

I'm not sure about the front wheels being driven, though. It seems that it takes a little driving and load on them to get them fully engaged, and it's hard to tell if both of them are actually driven or not. More testing will show what's going on --- now that I can shift to 4L that easyly, I can use it more.

Thank you all for your input! :)

If you have 4H and not 4L. You probably have a linkage issue to the t.case like the handle not going far enough forward to trip the front engage switch (that's if you have manual lever for 4x4). Or like wise if you have electrical transfer case you probably are not getting the signal to or from the servo's which engage the front axle, but that would affect both 4H and 4L. Either way if your front is locking in 4H and not 4L you do not have a problem with gas actuator which is what the posi lock replaces.

The transfer case has the manual lever. Unfortunately, there are not so many occassions that allow me to use 4wd. I'd need a large muddy field or some deeper sand for better testing and someone around to pull me out if I get stuck.

It can very well be that 4L just needs to get some usage to work better, but it can be anything else like a switch on the t.case or the actuator as well. Before I can try it out more seriously, I can't tell.

I hope that I can find time to go to Denmark soon where they have a beach you can drive on. That would be great for testing. It would be a nice trip for a weekend, about 1300km in total. Well, maybe next weekend ...

When the light comes on the transfer shifr lever for the front wheels the actuator is engaged. it won't light if the actuator is bad.

BTW
I forgot and was in 4H going 70 mph, and when I noticed, I reached down to the transfercase shft and pushed it up to 2H. It didn't make a sound.

Hmm, the light comes on, so the actuator might be ok. If it were bad, it wouldn't work in 4H, either, I think. But the light can be on no matter if the front wheels are driven or not. It appears to correspond to the position of the lever only.

The gearing of 4H<-->2H is syncronized. Take the load off the drivetrain (as you would when shifting gears without using the clutch on a manual), and you can shift it at any speed.

2H<-->N and N<-->4L are not synchronized, thus you cannot shift unless the gearwheels involved are spinning equally enough. If you get stuck in N, some of the gearwheels slow down and/or stop but others do not, and you must turn off the engine to get out --- at least with an automatic transmission. You might be able to just hold the clutch with a manual and all the gearwheels in the transfer case might stop. But if you're quickly enough, the gearwheels still spin equally enough to shift without grinding.

I have only shifted to 4 LOW while stopped my self and the tranny in park with all of my 4X4's. Because of the gear reduction change it would be hard on the tranfer case to try shifting on the "fly" to 4 LOW.

In park? Hmm ...

Well, I've been driving around and got some chance for more testing. Best way to get 4L going is driving 20 or 50 meters in 4H, then stop and put tranny into neutral, then quickly shift to 4L.

I've also found out that the transmission does stay in 1st gear if I'm in 4L and the front wheels are not driven. If the front wheels are driven in 4L, it shifts to 2nd and 3rd --- I didn't drive fast enough to find out if it would shift to 4th.

Now, how comes that 1st gear is sticky in 4L when the front wheels are not driven? How's that achieved, and how does the drivetrain 'know' wheather the front wheels are driven or not?

problem I have found with using neutral is that there is nothing keeping the tranny from turning and causing the input shaft of the transfer case to spin when you go thru transfer neutral. Using park will keep this from happening. I guess if your good and fast then you won't grind to much during the shifting.

Hm, I somehow thought the gears were supposed to spin so that they spin equally while shifting. I didn't dare to shift the t.case in park because I imagined that the transmission is blocked in park so that I would eventually damage something when shifting spinning gears at a blocked tranny.

Does this mean that you can get out of N when shifted to park without turning off the engine?

IF you are stopped, and the transmission is in park the you should be able to go to N and back out with no problem. However most of the time I get to N (transfer case) while not in park therefore the transmission spins when the transfer case hits N. The best way to recover from this is to shut off the engine so everything stops re-engage the T-Case and then start the engine. You can shift to 4H and back to 2WD while moving but for going to 4L you should come to a complete stop.

THX, I'll try to shift in park the next time :)

Can't you shift to park with the t.case stuck in N and thus get out?

not usually cause the tranny maybe turning and you going to park if everything is turning could cause damage to the park lock in the tranny. I have found the easyest and quickest way to get everything going again is to shut the engine off and shift transfer case out of N then restart engine. I only use this method if I have somehow hit N with the tranny out of park.

Ja, somethimes the lever just doesn't go fully through to 4L, and then I also stop the engine to get out of N. Yesterday, I once tried to shift to 4L in Park, but the t.case got stuck in N.

Anyway, I think 4L isn't brought in and it will work better after getting more usage :)

When the light comes on the transfer shifr lever for the front wheels the actuator is engaged. it won't light if the actuator is bad.

BTW
I forgot and was in 4H going 70 mph, and when I noticed, I reached down to the transfercase shft and pushed it up to 2H. It didn't make a sound.

The light wont come on on mine till it locks it sometimes takes a few seconds.
Quantam I do that all the time (makes me feel like an idiot) we need a light on the dash (at least I do)
I still dont understand why yall are stopping to go to 4L. I may be wrong but if you kick it into N before shifting to 4L and just BARELY let it roll it shifts sooooo much easier.
I have also learned not to wait till im stuck before using 4X4 :)