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Discussion Starter #1
My apologies if this has already been covered-

Is there a way to manually engage the clutch packs on an NV245 transfer case, such that the TC stays in high but 4wd is engaged?
Basically a 4-HI switch.

I don't like waiting for the ESP program to figure out 4wd is needed every time I start slipping in snow.

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Your Commander is always in 4Hi. In other words it is always in 4WD and can manually be put into 4Lo with the silver t-switch on the console.
 

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My apologies if this has already been covered-

Is there a way to manually engage the clutch packs on an NV245 transfer case, such that the TC stays in high but 4wd is engaged?
Basically a 4-HI switch.

I don't like waiting for the ESP program to figure out 4wd is needed every time I start slipping in snow.

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You are in 4-HI all the time as 5253 said.
 

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Discussion Starter #4
I guess I misunderstand how the TC works, then. I thought the clutches only engage if slipping is detected, but what you're saying is they are always engaged and just allow slipping based on road conditions?

I would think we'd have a lot more "Worn TC Clutch" codes if that were the case, but I very well could be wrong.

This came about because in snow driving, the truck feels like it will spin the back just a little before transferring torque to the front. I tested this on a corner and, while not scientific, it kicked the back end out like a RWD vehicle.

Thoughts?
 

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The NV245 acts as a rear-biased open transfer case in most situations. That's why you can get the back tires to spin a bit off the line; when you first launch the system naturally directs most power to the rear, then the clutches engage and disengage as necessary to redirect power. This is also why the clutches don't wear out too quickly; They're typically disengaged except when needed.


The system is pretty fast in its transitions between locked and unlocked, and it tries to predict slippage before it occurs to minimize it.
 

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Discussion Starter #6
That lines up with my experience, but I dislike this behavior in snow/ice as I mentioned.

Also makes a lot more sense, since 4LO locks the clutches (or does it bypass them?). So back to my quest for a true, locked-in 4HI.

Is there a way to manually trigger what I assume is a lockup solenoid? Mainly asking before I go digging in wiring and part diagrams.

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Discussion Starter #8
Thank you for finding that. Interesting read. So it definitely can be done.

All I want to do is lock up the clutches. Now 2LO... that would take some ingenuity and would most likely piss off the computers, unless you just rigged a full on bypass to the lockup solenoid. Would probably have to do ESP full off.

Ohh, I like where this is headed.

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It doesn't look like it'd be to difficult to replicate the results in the other thread; however, I don't see any way of doing that without tearing out the modules currently controlling everything. I can see it causing some major issues with other electronics, especially on QTII on QDII setups.

I also don't think 2LO is possible with our current transfer case, at least not without some serious modifications. From what I've read, the only transfer case in WK/XKs that can manage 2WD is the NV146 in the SRT Jeeps.
 

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It doesn't look like it'd be to difficult to replicate the results in the other thread; however, I don't see any way of doing that without tearing out the modules currently controlling everything. I can see it causing some major issues with other electronics, especially on QTII on QDII setups.

I also don't think 2LO is possible with our current transfer case, at least not without some serious modifications. From what I've read, the only transfer case in WK/XKs that can manage 2WD is the NV146 in the SRT Jeeps.
Sorry, 2Lo isn't quite what I ment. More like 4Lo Open as described in the referanced post.
 

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Discussion Starter #11
For some reason it seems pretty straightforward in my head to interrupt the signal going to the lockup solenoid and block/transmit a lockup depending on desire, or run it in passthrough mode.

Obviously I haven't done it, but it would be interesting to see how the software would handle this.

Perhaps there might need to be a "false lock" signal sent to the FDM for 4LO open.

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Discussion Starter #12 (Edited)
I also don't think 2LO is possible with our current transfer case, at least not without some serious modifications. From what I've read, the only transfer case in WK/XKs that can manage 2WD is the NV146 in the SRT Jeeps.
If the NV245 is an always-engaged open diff, which lines up with what I am reading, you are right.

For some reason I was thinking about the Patriot's 4wd system, that doesn't engage the other set of wheels (2wd) until it slips, then locks them together. At least, that's how I understood it when I owned one.

Edit because I forget if FD1 is front or rear wheel drive primarily.
 

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Discussion Starter #13
Ok, this is all making sense now. The NV245 is always in 4HI OPEN. That's what I wasn't getting.

I want 4HI LOCK without ESP intervention.

Thanks for your patience.

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Ok, this is all making sense now. The NV245 is always in 4HI OPEN. That's what I wasn't getting.

I want 4HI LOCK without ESP intervention.

Thanks for your patience.

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I'll be interested to see how your proceed with this and more importantly, what kind of results you get.

Personally, I think you're opening a big can of worms here - but hey, nothing ventured, nothing gained.
 

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Discussion Starter #15
I've done just a couple of hrs of quick research, and here's what I've come up with -
Manuals say the lock signal is communicated to the transfer case motor via the Can C bus, but wiring diagrams show only one wire going to the motor lock signal. By my not-so-professional knowledge, CAN requires two wires to transmit data. But the wiring diagram below shows only one wire (yellow/tan) going to the lock signal. Also note, the lockup and shifting seem to be controlled by the same motor assembly. Not sure how that works, but that's what I see.

Path forward:
  • Measure before/after low shift voltage on this wire (4WD low locks the clutch packs)
  • If it's a constant voltage, that wire should be able to be spliced and with a diode protecting the FDCM, voltage applied for manual clutch lockup.
  • I'm envisioning a bypass/lockup switch.
Wiring diagram attached below.

TC_motor_wiring.JPG


Comments anyone?
 

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I've done just a couple of hrs of quick research, and here's what I've come up with -
Manuals say the lock signal is communicated to the transfer case motor via the Can C bus, but wiring diagrams show only one wire going to the motor lock signal. By my not-so-professional knowledge, CAN requires two wires to transmit data. But the wiring diagram below shows only one wire (yellow/tan) going to the lock signal. Also note, the lockup and shifting seem to be controlled by the same motor assembly. Not sure how that works, but that's what I see.

Path forward:
  • Measure before/after low shift voltage on this wire (4WD low locks the clutch packs)
  • If it's a constant voltage, that wire should be able to be spliced and with a diode protecting the FDCM, voltage applied for manual clutch lockup.
  • I'm envisioning a bypass/lockup switch.
Wiring diagram attached below.

View attachment 40640

Comments anyone?
I haven't yet pulled one of these apart. From my understanding the "Transfer Case Motor Lock" is a lock on the motor to keep it from turning or back winding unless you want it to shift . The locking of the transfer case for 4 Lo is a mechanical engagement at the far end of the shift stroke that doesn't use the clutch pack at all, and the variable limited slip in normal mode is caused by the shifting fork moving to increase the pressers on the clutch pack. Again I have not pulled one of the apart, this is my understanding from diagrams and online research.
 

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I haven't yet pulled one of these apart. From my understanding the "Transfer Case Motor Lock" is a lock on the motor to keep it from turning or back winding unless you want it to shift . The locking of the transfer case for 4 Lo is a mechanical engagement at the far end of the shift stroke that doesn't use the clutch pack at all, and the variable limited slip in normal mode is caused by the shifting fork moving to increase the pressers on the clutch pack. Again I have not pulled one of the apart, this is my understanding from diagrams and online research.
Let me restate some of that. As I understand it, the Transfer Case Motor Lock signal unlocks the motor to allow a shift or adjustments to happen. As a fail safe, at rest or 0 signal the motor is locked.
 

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Discussion Starter #18
Yeah, I just re-read through the other thread. It seems the motor does both clutch pack lock and shifting?

But I think you're right on about the motor lock. Which leaves the only way to lock 4HI as a PWM signal to the motor, which would royally screw with the FDCM. Dang.
 

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Yeah, I just re-read through the other thread. It seems the motor does both clutch pack lock and shifting?

But I think you're right on about the motor lock. Which leaves the only way to lock 4HI as a PWM signal to the motor, which would royally screw with the FDCM. Dang.
Please, if you find out different let me know. From the time I bought my Commander I wanted the ability for 4 Hi lock, but to be truthful haven't needed it and Iv'e been in some pretty sloppy stuff with it.
 
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