Transfer Case Stuck in 4H

[Exposure]

G'day,

I purchased a 2000 R50 Pathfinder recently with the electric transfer case. It appears as if the transfer case is stuck in constant 4x4H mode. I've run the diagnostic that is built into the system and no faults log, I can select all of the modes and the system believes it is engaging by just a single beep. I can switch between 4H and 4L fine, but I cannot seem to get the wet clutch pack to disengage and go into 2wd mode.

I've done all manner of forwards and reverse, full lock to full lock on and off tarmac and nothing works. I've changed the fluid in the transfer case, the stuff that came out did not have any chunks in it and didnt look too bad.

Considering no faults are indicated and everything appears to switch with no issue, a friend suggested the clutch pack itself may be stuck together. Has anyone experienced this before? Are there any additives I could try and add to the transfer case to try free them up?

cheers,

Nik

[onespiritbrain]

When you place the switch in 2H does the little picture on the dash show the front two wheels blinking? Also does it beep when switching to the 2H position?

 

Is the transfercase locked (orange block in center of little dash pic)? If so, have you tried placing the switch in 2H while on pavement and then put the trans in reverse and cut the steering wheel all the way and drive in backward circles? That will greatly stress the transfercase and may break loose whatever is stuck.

 

If you try the above, can you feel the tires grabbing and barking?

 

Edit: I see the full lock to full lock now but did you try that in reverse also? And, while my transmission died anyway, I did have some significant success with Seafoam Transtune. It’s basically just alcohol but it can be used in most hydraulic systems and might just do the trick for you.

 

Sent from my iPhone using Tapatalk

 

[Exposure]

When I move the switch position it does it's single beep and the lights indicate what they should. Currently when I switch to 2wd it does a short single beep and only the rear two wheel lights are illuminated. The centre diff light is not.

 

I have tried full lock on gravel and over pavement back to gravel with the switch in the 2wd position to try get it unstuck. The tyres do grab and then eventually let go or slip as the transmission gets wound up. Driving on the road when I need to do tight corners it winds up and requires more accelerator to move. Eventually the tyres do slip or chirp on the pavement to relive some of the wound up forces.

 

Do you think doing it in reverse will stress it more or produce a different outcome?

[onespiritbrain]

Hmmmmmmm... if only the two rear wheels are lit then you should be in 2H. I’m not sure where the sensor is or what exactly it is looking at to determine whether or not 4WD is fully engaged or disengaged but when mine isn’t fully engaged the wheels blink until the movement is completed.

We need to search for a write up that I have seen before that shows what everything looks like inside the transfercase. I don’t have my laptop with me right now but the service manual might help here as well. Do you have a service manual?


Sent from my iPhone using Tapatalk

[Exposure]

Yeah the system seems to think all is right and it's in 2H. I have a copy of the service manual, when there is no pressure going to the wet clutch they should disengage, but it doesn't appear to do that.

 

I've run through the built in diagnosis that it has. No fault codes were logged, but now that I've driven it a bit more maybe I'll try that again. I do not believe it is an electrical fault as the system is designed to pick those up.

[hawairish]

Hey Nik,

 

Welcome to the forums.  I have a few outlier presumptions:

1. ATF fluid filled to the fill hole level
2. All the tires are matching in brand, size, and similar tread life
3. No other dash lights, such as ABS
4. It doesn't have manual wheel hubs (it's a pretty common upgrade, though not normally done on the all-mode trucks)
5. 2wd hasn't worked since you've gotten it (did it come with this issue?)

It does seem more mechanical than electrical if the indicators show it as being in 2wd and no other faults.  Like onespiritbrain, I'd think the turning and driving would force it loose.  You could try to eliminate a mechanical issue from an electrical one by putting the truck in 2wd for a little bit, do some circles, then park and shut the truck off.  Then, lift a tire off the ground and give it a spin—if the driveshaft spins freely, then at least you'd know if the transfer motor and clutches were capable of releasing to be in 2wd.  If it remains engaged, would seem mechanical to me.

[Exposure]

Hi, thank you.

 

All of those 5 assumptions are correct. I changed the transfer case fluid because I read that could help.

 

That is a good idea, I'll give that a go to confirm my suspicion that it is the clutch packs stuck together. The system appears to work correctly, as in the switching and light indications however it remains stuck in 4H.

 

 

[Exposure]

Just an update: I remembered a friend was helping me with the car before when it was on jacks and off. A back wheel was turned and the opposite side front wheel turned with it. The car was off and it was in 2H before it was turned off.

 

I think that confirms it's a mechanical issue, and the fact no codes come up seems to indicate the clutch plates are stuck together.

[onespiritbrain]

You might try a pint of Seafoam Transtune. It is advertised as compatible with most hydraulic systems including automatic transmissions, so it is certainly safe in a transfercase, even if it’s an ATX14A.


Sent from my iPhone using Tapatalk

[Exposure]

13 hours ago, onespiritbrain said:

You might try a pint of Seafoam Transtune. It is advertised as compatible with most hydraulic systems including automatic transmissions, so it is certainly safe in a transfercase, even if it’s an ATX14A.


Sent from my iPhone using Tapatalk

Okay thanks, I'll give that a go.

 

Are you meant to leave it in for a few days or just a few kilometres?

 

Nik

[Exposure]

On 10/10/2018 at 4:53 PM, Exposure said:

Okay thanks, I'll give that a go.

 

Are you meant to leave it in for a few days or just a few kilometres?

 

Nik

Well I've had that stuff in for a week, no change

[onespiritbrain]

Hmmmmm.. well I have one more idea but it could damage the transfer case.

Put it in 4LO and drive at 50mph for 10min or so. Hop out and put your hand on the transfer case real quick to confirm it is HOT. If it’s not hot, keep driving.

While it’s hot, do the forward and reverse lock to lock figure 8’s. And be aggressive with it.

Is your set up the dual switches or the single switch with a floor lever?

[onespiritbrain]

On second thought, this could also overheat your transmission..

Where are you located?


Sent from my iPhone using Tapatalk

[Exposure]

9 hours ago, onespiritbrain said:

On second thought, this could also overheat your transmission..

Where are you located?


Sent from my iPhone using Tapatalk

Mine is the transfer with the dash mounted switch.

 

I'm in Brisbane, Australia.

 

I thought about trying reverse figure 8s as I've only done the forward ones before. I might also try draining and filling up the TC a few more times to ensure 100% all of the old fluid is out.

[onespiritbrain]

Oh yeah man doing it in reverse does the trick during common sticking. My wife’s truck gets stuck sometimes because she never ever uses it and only reverse gets it unstuck.


Sent from my iPhone using Tapatalk

[onespiritbrain]

I was going to say that I might hook you up with the spare I have but you’re waaaaay away :]

[Slartibartfast]

I'd be inclined to try the figure 8s in reverse at low speed, but I'd be concerned about damaging something elsewhere in the system by beating on it too far beyond that. If the backwards routine doesn't do it, it may be time to just drop the case and pull it apart. That said, having looked through the section in the manual that covers that box, I can understand not wanting anything to do with opening it up. TF-145 of the '03 R50 FSM has a procedure for looking into "tight corner braking symptom," which I'm guessing is just a really stupid way of saying "torque bind" or "stuck in 4x." Looks like the procedure boils down to checking for power from pin 34 in the connector to ground. If it's there, check the clutch pressure switch circuit; if it's not, tear the thing down and check the control valve assembly, 4WD solenoid valve, 2-4WD shift solenoid valve, clutch piston, and clutch assembly.

 

If you jack up one of the front wheels with the engine off, can you turn that wheel without moving the truck? If not, the problem's probably in the clutch or maybe the piston. Looks like wet clutches on motorbikes tend to lock up from sitting, but that's because they sit with the clutch fully engaged; if I'm understanding this thing right, the clutch should be disengaged with the truck shut off, so that doesn't make a whole lot of sense. If turning the truck off releases the clutch, I'd suspect a hydraulic fault (solenoid stuck open). The lack of codes suggests it's probably not wiring, except that the last step in the troubleshooting is to check the connector for loose or damaged pins, so maybe have a look at that as well before tearing the whole case apart.

Good luck! If you haven't yet, you can get the US manuals here. I'm not sure how much will hold true for your Aussie model, though.

[Exposure]

Thanks for the thought onespiritbrain.

 

I've had the car off up on jacks for something else, turning the rear right wheel made tb front left turn. That means the centre is still locked right?

 

Yeah I've been using US manuals, 2001 or 2002 onwards has the transfer case I have with the switch.

 

Good idea on checking the connector for obvious damage. Do you mean the connectors on the transfer case or the connectors on the transfer control module?

 

I'll try drive in reverse at slow speed and figure 8s, then if that doesn't work I'll try follow that trouble tree and check the connector. 

 

I'd think that if there was a pressure switch or valve stuck open that the built in diagnostic would pick it up, but so far nothing comes up. It behaves normally switching all the modes as well with a single beep and corresponding lights.

Thanks for all the suggestions, I'll give them a go.