Americas diff lock issues, cross posted on the FB US Grenadier owners page

bamanuke · Dec 22, 2023

picked up the Gren Saturday, really impressed until today. decided to try the center diff (worked great), then the lockers(not good). I have the "rough pack). rear engaged fine, front would not. went through all the normal stuff, ended up with error messages for both front and rear. called the dealer, was told to try applying the parking brake , which I did and was able to get both front and rear to engage. tried again 45 minutes or so later, rear engaged front wouldn't. disengaged the rear, flashing red diff lock icons for both, wouldn't clear even after disengaging center diff. rear diff and front diff error messages, only clear after the vehicle has been shut off for several minutes. anyone else dealing with this?

ADVAW8S · Dec 22, 2023

bamanuke said:
picked up the Gren Saturday, really impressed until today. decided to try the center diff (worked great), then the lockers(not good). I have the "rough pack). rear engaged fine, front would not. went through all the normal stuff, ended up with error messages for both front and rear. called the dealer, was told to try applying the parking brake , which I did and was able to get both front and rear to engage. tried again 45 minutes or so later, rear engaged front wouldn't. disengaged the rear, flashing red diff lock icons for both, wouldn't clear even after disengaging center diff. rear diff and front diff error messages, only clear after the vehicle has been shut off for several minutes. anyone else dealing with this?

Is the diff not engaging or is it flashing on the screen? Where did you try it, grass, mud?

rovie · Dec 22, 2023

bamanuke said:
picked up the Gren Saturday, really impressed until today. decided to try the center diff (worked great), then the lockers(not good). I have the "rough pack). rear engaged fine, front would not. went through all the normal stuff, ended up with error messages for both front and rear. called the dealer, was told to try applying the parking brake , which I did and was able to get both front and rear to engage. tried again 45 minutes or so later, rear engaged front wouldn't. disengaged the rear, flashing red diff lock icons for both, wouldn't clear even after disengaging center diff. rear diff and front diff error messages, only clear after the vehicle has been shut off for several minutes. anyone else dealing with this?

I had exactly the same experience once at the very beginning on a damp meadow. Ride on a loose or slightly sticky surface and shift locks first at the rear and then at the front while rolling very slowly.

Clark Kent · Dec 22, 2023

I'm a strong fan of having a working knowledge about how something works before you operate it. I'm making zero assumptions here so my apologies if you know this stuff already.

The e-locker uses a ramp and pin arrangement to lock the side gears. There's some variation in the designs. To my knowledge no one has confirmed the specific mechanism used in the Grenadier lockers but it's going to be something of that nature.

The lock/unlock sequence requires a small amount of axle rotation (vehicle movement) to take effect. My best tip is to study the Harrop video (link below) and think about how that applies out on the track. You need to allow some axle rotation for the diff to lock. Same for unlock, and especially if the diff is under tension from axle wind-up. The 2nd benefit of knowledge is having a mechanical sympathy for what's occurring so you should play nice while the locker is changing states.

View: https://youtu.be/nT_H6rpd-Ck?feature=shared

bamanuke · Dec 22, 2023

ADVAW8S said:
Is the diff not engaging or is it flashing on the screen? Where did you try it, grass, mud?

pasture , hard ground . rear engaged first try, front did not, second time neither, third both, 4th rear only. corresponding error messages every time. super slow speed or in N or P, tried it all. whether or not there was actual engagement, eh felt like it when displayed, sorta when not. nothing challenging to determine.

Clark Kent said:
I'm a strong fan of having a working knowledge about how something works before you operate it. I'm making zero assumptions here so my apologies if you know this stuff already.

The e-locker uses a ramp and pin arrangement to lock the side gears. There's some variation in the designs. To my knowledge no one has confirmed the specific mechanism used in the Grenadier lockers but it's going to be something of that nature.

The lock/unlock sequence requires a small amount of axle rotation (vehicle movement) to take effect. My best tip is to study the Harrop video (link below) and think about how that applies out on the track. You need to allow some axle rotation for the diff to lock. Same for unlock, and especially if the diff is under tension from axle wind-up. The 2nd benefit of knowledge is having a mechanical sympathy for what's occurring so you should play nice while the locker is changing states.

View: https://youtu.be/nT_H6rpd-Ck?feature=shared

Thanks Mr. Kent! Looks like it was all operator error, not being familiar with diff locks and impatience. After a few more attempts this morning, I believe I've got it figured out, thanks to your advice. Here's what worked for me---low range, center diff locked, slowly moving forward. press the rear diff lock and hold until it begins blinking, do not expect it to immediately engage, maybe 10 seconds, repeat for the front. You should get locked indications on the screen. Disengaging took quite a bit more maneuvering and time, maybe 2minutes or more moving slowly and turning left to right. Don't expect instant gratification when operating these lockers. Thanks again!

Clark Kent · Dec 22, 2023

bamanuke said:
pasture , hard ground . rear engaged first try, front did not, second time neither, third both, 4th rear only. corresponding error messages every time. super slow speed or in N or P, tried it all. whether or not there was actual engagement, eh felt like it when displayed, sorta when not. nothing challenging to determine.

Thanks Mr. Kent! Looks like it was all operator error, not being familiar with diff locks and impatience. After a few more attempts this morning, I believe I've got it figured out, thanks to your advice. Here's what worked for me---low range, center diff locked, slowly moving forward. press the rear diff lock and hold until it begins blinking, do not expect it to immediately engage, maybe 10 seconds, repeat for the front. You should get locked indications on the screen. Disengaging took quite a bit more maneuvering and time, maybe 2minutes or more moving slowly and turning left to right. Don't expect instant gratification when operating these lockers. Thanks again!

Happy to help. Glad you sorted it out.
As far an unlocking goes, it's been well discussed here that the locker unlocks quickly but the light in the switch does not go off until the wheel speed sensors (part of ABS, etc), detect a difference in wheel (axle) speeds to confirm that the diff is unlocked. That's a bit confusing until you understand why there can be a delay between selecting OFF and the light going off.

bamanuke · Dec 23, 2023

Clark Kent said:
Happy to help. Glad you sorted it out.
As far an unlocking goes, it's been well discussed here that the locker unlocks quickly but the light in the switch does not go off until the wheel speed sensors (part of ABS, etc), detect a difference in wheel (axle) speeds to confirm that the diff is unlocked. That's a bit confusing until you understand why there can be a delay between selecting OFF and the light going off.

great to know! I thought that I did a quite thorough search on here prior to posting, anyway, thanks for the guidance!

nuclearbeef · Dec 24, 2023

My rear won't engage.
Just flashes both on button and on telltale. Never indicates a fault, just never engages.
Driving in circles on grass in both directions did not solve the problem.
Locker definitely not locked and lights continued to flash.

Had to disengage the center locker and drive circles again to make it stop flashing.

Clark Kent · Dec 24, 2023

nuclearbeef said:
My rear won't engage.
Just flashes both on button and on telltale. Never indicates a fault, just never engages.
Driving in circles on grass in both directions did not solve the problem.
Locker definitely not locked and lights continued to flash.

Had to disengage the center locker and drive circles again to make it stop flashing.

Confirm that you are in Low Range? The lockers don't operate in High Range. Just checking

If you have a voltmeter there is an accessible plug in the loom that supplies power to the rear locker. The plug is on the inside of the frame for the left lower control arm mount. This pic is looking rearwards from the transfer case towards the left rear wheel. I've pulled the plug apart so you can spot it.
If everything is in order you should have power at the vehicle side of the plug with the ignition ON, rear locker ON, in Low Range and the CDL is locked. If there is no power you may have a fuse, wiring, selection or switch fault. If there is power at the plug then the fault is towards the locker. Either way it's a dealer issue but it would be a quick test to confirm if power is going to the locker.

rovie · Dec 24, 2023

Clark Kent said:
Confirm that you are in Low Range? The lockers don't operate in High Range. Just checking

If you have a voltmeter there is an accessible plug in the loom that supplies power to the rear locker. The plug is on the inside of the frame for the left lower control arm mount. This pic is looking rearwards from the transfer case towards the left rear wheel. I've pulled the plug apart so you can spot it.
If everything is in order you should have power at the vehicle side of the plug with the ignition ON, rear locker ON, in Low Range and the CDL is locked. If there is no power you may have a fuse, wiring, selection or switch fault. If there is power at the plug then the fault is towards the locker. Either way it's a dealer issue but it would be a quick test to confirm if power is going to the locker.

Hi @Clark Kent , that's a good tip for him. I know the test with the plug too.
But I don't think it's due to the power supply. The function of the diff locks is tested before delivery. At least that's what my dealer confirmed to me.
@nuclearbeef , after you have shifted to Low, as Clark Kent also noted, drive at a very slow speed and then press the button and hold it down for at least 1 second.
During my first test with my vehicle in April, I had the same experience as you.

Clark Kent · Dec 24, 2023

rovie said:
Hi @Clark Kent , that's a good tip for him. I know the test with the plug too.
But I don't think it's due to the power supply. The function of the diff locks is tested before delivery. At least that's what my dealer confirmed to me.
@nuclearbeef , after you have shifted to Low, as Clark Kent also noted, drive at a very slow speed and then press the button and hold it down for at least 1 second.
During my first test with my vehicle in April, I had the same experience as you.

Hi @rovie I'm a long way down the probability scale here, but it's something @nuclearbeef can check next, assuming that finger trouble and gear selections are not involved. Also sharing this info here for wider interest. Hopefully it's just a 'digital' calibration error (perhaps the right index finger?)

rovie · Dec 24, 2023

Clark Kent said:
Hi @rovie I'm a long way down the probability scale here, but it's something @nuclearbeef can check next, assuming that finger trouble and gear selections are not involved. Also sharing this info here for wider interest. Hopefully it's just a 'digital' calibration error (perhaps the right index finger?)

It's all good, I meant it in a positive way that you gave the hint here for everyone. I didn't want it to come across the wrong way. I just wanted to give hope that by trying again it might work after all. I couldn't get it to work the very first time either and wanted to contact the dealer. But it was Sunday and I wouldn't have been able to reach him. So I tried again and lo and behold. It worked. Today I switch the locks on and off without any problems.

Clark Kent · Dec 24, 2023

rovie said:
It's all good, I meant it in a positive way that you gave the hint here for everyone. I didn't want it to come across the wrong way. I just wanted to give hope that by trying again it might work after all. I couldn't get it to work the very first time either and wanted to contact the dealer. But it was Sunday and I wouldn't have been able to reach him. So I tried again and lo and behold. It worked. Today I switch the locks on and off without any problems.

Yep, that's how I took your post. All good!

We have US$50M aircraft at work that will recover from some faults just by cycling the power and computers. Sometimes you just have to give it another go.

nuclearbeef · Dec 24, 2023

Could be I didn't press the button correctly. I'll try again when I get a chance. I'm a 5.5 hour drive from the dealer, so rather solve it here.

I'm in low with centre locked.
pressed the button in the same sequence as the offload button... long press followed by a confirmation press. right???

Anyway, would I get the rear diff lock icon on the telltale display flashing if it wasn't attempting to lock the rear?
The centre flashes for a short time then displays solid when it locks.
Rear just continues flashing.

Oh, and thanks for the help. I'm usually not the moron, but we all have our moments.
It's not like I read the manual or anything.

Michael H. · Dec 24, 2023

nuclearbeef said:
Could be I didn't press the button correctly. I'll try again when I get a chance. I'm a 5.5 hour drive from the dealer, so rather solve it here.

I'm in low with centre locked.
pressed the button in the same sequence as the offload button... long press followed by a confirmation press. right???

Possible that this is your problem … It's just a one second press of the button (as it says in the manual

) … not “a long press followed by a confirmation press”.

Give that a try and see what happens.

rovie · Dec 24, 2023

nuclearbeef said:
Could be I didn't press the button correctly. I'll try again when I get a chance. I'm a 5.5 hour drive from the dealer, so rather solve it here.

I'm in low with centre locked.
pressed the button in the same sequence as the offload button... long press followed by a confirmation press. right???

Anyway, would I get the rear diff lock icon on the telltale display flashing if it wasn't attempting to lock the rear?
The centre flashes for a short time then displays solid when it locks.
Rear just continues flashing.

Oh, and thanks for the help. I'm usually not the moron, but we all have our moments.
It's not like I read the manual or anything.

Press 2x only for offroad mode. Not for locks. Simply hold for at least 1 second.
Now I realise why the light is flashing, you have switched it off again by pressing the 2nd time. Good luck, I hope it works then.

nuclearbeef · Dec 24, 2023

Michael H. said:
Possible that this is your problem … It's just a one second press of the button (as it says in the manual ) … not “a long press followed by a confirmation press”.

Give that a try and see what happens.

rovie said:
Press 2x only for offroad mode. Not for locks. Simply hold for at least 1 second.
Now I realise why the light is flashing, you have switched it off again by pressing the 2nd time. Good luck, I hope it works then.

That worked!
Thanks guys.
All working properly. I must have thoroughly confused the system with my multiple presses.

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Americas diff lock issues, cross posted on the FB US Grenadier owners page

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