N

Norler

Member
Hello!
I've got a pretty steep uphill driveway. It's pure gravel and ends in a sharp 100 degrees turn onto asphalt. When taking this turn the front tires skids like ****. I've heard something about the center diff automatically locks itself when the car senses any wheel slipping. Can this be the actual case, and how may I confirm it? Any thoughts? 😊
 
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Norler said:
I've heard something about the center diff automatically locks itself when the car senses any wheel slipping. Can this be the actual case, and how may I confirm it? Any t
Click to expand...
Hi
For slipping wheels the DSC should kick in, are you climbing with DSC switched off?
1. did you try to select the terrain response "grass/gravel/snow" option before you climb ?
2. if not disabled can you see the DSC warning flashing while the wheels are spipping?
3. do you have locking rear diff?

or 4... the most important... did you read the basics in the owner's hanbook as to know how to correctly drive your vehicle ? no offence but if you didnt then start with that and maybe you'll realise it's just an "operator error" cos the D4 is very capable to manage such things once it's properly used ;)
 
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sierrafery said:
Hi
For slipping wheels the DSC should kick in, are you climbing with DSC switched off?
1. did you try to select the terrain response "grass/gravel/snow" option before you climb ?
2. if not disabled can you see the DSC warning flashing while the wheels are spipping?
3. do you have locking rear diff?

or 4... the most important... did you read the basics in the owner's hanbook as to know how to correctly drive your vehicle ? no offence but if you didnt then start with that and maybe you'll realise it's just an "operator error" cos the D4 is very capable to manage such things once it's properly used ;)
Click to expand...
DCS does not kick in. Car does not give any electronic feedback in any way. Have not tried with DCS switched off. Will try.

1. No. All in normal mode (selector to the left).
2. Wheels hardly slip on the gravel when driving up my driveway. Car must be extremely sensable if it takes action of some sort.. DCS does not flash.
3. Yes. Confirmed off. Rear diff spins freely.
4. Yes😁😉

Driving along pure asphalt it turns normal with no skidding on the front wheels. Perhaps the Gap tool can confirm center diff lock on or off?
 
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Norler said:
DCS does not kick in. Car does not give any electronic feedback in any way. Have not tried with DCS switched off. Will try.

1. No. All in normal mode (selector to the left).
2. Wheels hardly slip on the gravel when driving up my driveway. Car must be extremely sensable if it takes action of some sort.. DCS does not flash.
3. Yes. Confirmed off. Rear diff spins freely.
4. Yes😁😉

Driving along pure asphalt it turns normal with no skidding on the front wheels. Perhaps the Gap tool can confirm center diff lock on or off?
Click to expand...

So this is when driving down your drive?
It is unlikely you have a rear diff lock, it was an expensive option, on the L322, so probably yours too.
The center diff (and rear if you have) should be able to be monitored on the 4X4 screen on the info screen.
Suggest you try a different a different terrain position on the switch.

We often drive up a hill with no issues, but use Hill Decent on the way down. Feet off the pedals all you do is steer.
So I would suggest you look further at your answer to number 4, and try a different setting.

J
 
marjon said:
The center diff (and rear if you have) should be able to be monitored on the 4X4 screen on the info screen.
Click to expand...
what he said^^^ as about how the central diff works here's from the WSM:

"The transfer box receives a torque input from the transmission output shaft, which is passed through the unit to two outputs for the front and rear drive shafts.

The input torque is equally distributed via a bevel gear type differential. In order to provide an optimal torque distribution to each wheel in all driving conditions, the unit is equipped with an electronically controlled locking and torque-biasing device. This device detects wheel slip via various vehicle system inputs to the transfer box control module and locks the differential accordingly. The locking torque is applied through a multi-plate clutch assembly.

A planetary gear set, located in the differential assembly, allows the driver to select high or low range whilst driving, this is known as 'shift on the move'. When in low range, the planetary gear set provides a ratio of 2.93:1, which gives the vehicle an extremely low crawl speed for off road driving and trailer towing. High range is a direct drive from the transmission output shaft and provides a 1:1 ratio.

Both the centre differential locking and biasing and the 'shift on the move' features are actuated via a DC transfer box motor, which is controlled by the transfer box control module, via a Pulse Width Modulation (PWM) signal."

Norler said:
Perhaps the Gap tool can confirm center diff lock on or off?
Click to expand...
I have no experience with Gap tool but if you have an inputs section for the transfer box the motor's status should be visible
 
marjon said:
So this is when driving down your drive?
It is unlikely you have a rear diff lock, it was an expensive option, on the L322, so probably yours too.
The center diff (and rear if you have) should be able to be monitored on the 4X4 screen on the info screen.
Suggest you try a different a different terrain position on the switch.
Click to expand...
Uphill 30° incline (at most) on gravel into a tight 100° turn onto asphalt. Diff locking does not monitor in selector mode "special programs off". Here is a picture of diff monitoring in a "special program":
 

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sierrafery said:
what he said^^^ as about how the central diff works here's from the WSM:

"The transfer box receives a torque input from the transmission output shaft, which is passed through the unit to two outputs for the front and rear drive shafts.

The input torque is equally distributed via a bevel gear type differential. In order to provide an optimal torque distribution to each wheel in all driving conditions, the unit is equipped with an electronically controlled locking and torque-biasing device. This device detects wheel slip via various vehicle system inputs to the transfer box control module and locks the differential accordingly. The locking torque is applied through a multi-plate clutch assembly.

A planetary gear set, located in the differential assembly, allows the driver to select high or low range whilst driving, this is known as 'shift on the move'. When in low range, the planetary gear set provides a ratio of 2.93:1, which gives the vehicle an extremely low crawl speed for off road driving and trailer towing. High range is a direct drive from the transmission output shaft and provides a 1:1 ratio.

Both the centre differential locking and biasing and the 'shift on the move' features are actuated via a DC transfer box motor, which is controlled by the transfer box control module, via a Pulse Width Modulation (PWM) signal."


I have no experience with Gap tool but if you have an inputs section for the transfer box the motor's status should be visible
Click to expand...
No luck with Gap tool i'm afraid..
But then I guess the car does whatever it pleases in the "Special programs off" mode without leaving any details of what it actually does🫤
 

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Hi

Have u checked ur steering wheel angle sensor is correct plse as in zero with the wheels dead straight

Also see you have selected Lo range when going up the hill

Will it go up the hill in high without using any of the terrain response settings plse

Hope that also helps with everyone else’s comments
 
gstuart said:
Hi

Have u checked ur steering wheel angle sensor is correct plse as in zero with the wheels dead straight

Also see you have selected lo range when going up the hill

Will it go up the hill in high without using any of the terrain response settings

Hope that also helps with everyone else’s comments
Click to expand...
I will check that steering angle sensor!

Not using any terrain respons settings aka. "Special programs off". Picture attached just to show what is not available in "Special programs off".
 
Norler said:
I will check that steering angle sensor!

Not using any terrain respons settings aka. "Special programs off". Picture attached just to show what is not available in "Special programs off".
Click to expand...

Ah I see, apologises as thought that was a screenshot showing low range

No probs and worth checking, also doesn’t hurt to double check ur wheel speed sensors are all reading correctly

Surprised there arnt any fault codes with the special programs off , does it come up straight away or after a little while

If it does come up straight away would ensure ur battery with the engine off is a min of 12.6 Vdc

Hope that also helps
 
gstuart said:
Ah I see, apologises as thought that was a screenshot showing low range

No probs and worth checking, also doesn’t hurt to double check ur wheel speed sensors are all reading correctly

Surprised there arnt any fault codes with the special programs off , does it come up straight away or after a little while

If it does come up straight away would ensure ur battery with the engine off is a min of 12.6 Vdc

Hope that also helps
Click to expand...
Norwegian here so there will be some clearification lost in my translation😅

Special programs off appears immediatly.
 
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Norler said:
Special programs off appears immediatly.
Click to expand...
That's a selectable option which you can change in what you want based on the driving conditions, it's used for simple on-road driving, for off-road there are all those other options which's functionality is described in the owmner's manual ... IMO if there was a system fault that should have been revealed with a warning message, as long as no message points to a fault or error in the message centre it's nothing wrong with the vehicle just a lack of knowledge about how it works hence point nr 4 in my first reply

1727726843094.jpeg
 
Tested / observed several things today on a flat surface.

- Steering angle sensor measures 600° to 0° to -599°.
Measures around 0° when driving in a straight line with steering wheel centered. So sensor all good👍

- Grass-gravel-snow (display shows both diff lock open) -still skidding when turning.

- Ride height makes no difference.

- No visible play in suspension, ball joints, steering rack etc.

-Tire sidewalls (and the rims) straight down when driving in a straight line. Does not change when driving forwards and then backwards.
When turning max left, the left front wheel tire sidewalls bends heavily towards the car. And vice versa when turning to the right.

Also I think the inner wheel in a turn leans outwards a good amount. See picture. Is this normal?
 

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