Odd 'Grinding' when loss of tracion

[DannyBoy]

When I was out the other weekend I noticed an odd grinding sound when i was 4WD'ing you can hear it this video:
https://www.youtube.com/watch?v=7snNQzRhpVs

I was in 4Low and it can only be heared once ive lost tracion, cant hear while driving anywhere else.

Any help much appreciated!

 

[nathand22]

Its the traction control , it works by using the ABS so the noise you can hear is the ABS control unit pulsing, Totally normal

 

[nathand22]

actually after listening to the video it sound like a cv or diff issue.
i said Traction control before watching the vid

 

[DannyBoy]

oh good to hear, it sounds terrible inside lol. is the ABS still active even when VDC is off during 4L?

 

[DannyBoy]

shouldnt I get the noise constantly when driving on / off road?

 

[nathand22]

It could have something to do with the traction control itself or that it is forcing the power to be shifted to a dodgy corner of the driveline?
I would definitely get it sussed out, is it still under warranty?

If it is dont tell them you herd it on a trail, just tell them you herd it turning across the culvert on the side of a road while chucking a u-turn for eg just dont say you were out on a trail.

 

[nathand22]

oh good to hear, it sounds terrible inside lol. is the ABS still active even when VDC is off during 4L?

VDC vehicle dynamic control is different to ABLS (traction control) they both use the same system with the ABS but the VDC also controls throttle input or stop power where as the ABLS active brake limited slip is only using the ABS.

so bottom line is te ABLS is on 100% of the time and its only the VDC that can be and is automatically turned off.

 

[DannyBoy]

oh ok thanks for that.

yeah still under warranty, will post back with the out come.

cheers mate!

 

[leo d40]

Yeah I get the same grinding noise in low range when I break traction. The traction control light flashes on the dash (it's the light to the right of the vdc off light). It doesn't happen all the time but when it does it's bloody annoying. There's gotta be a fuse I can pull!

 

[nathand22]

Yeah I get the same grinding noise in low range when I break traction. The traction control light flashes on the dash (it's the light to the right of the vdc off light). It doesn't happen all the time but when it does it's bloody annoying. There's gotta be a fuse I can pull!

When the ABLS is activated or firing there is a bit of a noise but it shouldnt be as loud as in the vid, thats way louder then i ever heard mine, dont get me wrong you could hear it and actually feel it in the cab slightly through the peddle but in the video it comes across as about three or four times louder then it should be.

I wouldnt pull the fuse, with out the traction control you are back to standard open diff front and rear and even when you put the LOKKA in Dave you will still want the rear to be getting help from the ABLS.

 

[DannyBoy]

Im pretty sure ive heard the same noise coming from front during 4L and loss of tracion. Since nissan and my mechanic arnt open today im going to jack it up and turn each wheel check for any noise

 

[nathand22]

Im pretty sure ive heard the same noise coming from front during 4L and loss of tracion. Since nissan and my mechanic arnt open today im going to jack it up and turn each wheel check for any noise

It could be the noise just seems super loud on the video, BUT you will get the noise that the traction control makes from any corner of the car as the ABLS (traction control) works on all four wheels.

What is happening is that the ABS control unit is monitoring all four wheels all the time.
When it reads that one wheel is spinning faster then another it applies the brakes in a pulsing fashion to the wheel that is spinning faster, 99% of the time it is the wheel with the LEAST amount of traction, this then forces the power to drive through the other axial onto the wheel that isnt spinning which in 99% of the time is the wheel with the MOST amount of traction and there for gets the car moving again.
It can do this to one or more wheels at any one time and its the reason why in different situations the noise will be heard from the font or the back or both.

My concern was how loud that sound comes across on the video, i never heard mine that loud nor have i heard any other that loud and ive now been out with a stack of D40 that are equipped with the ABLS system, yes they all make a noise when it is activated but none of them have appeared that loud.

As i said it may just seem louder on the vid then it actually is, maybe you can confirm how loud the noise is to you while on the ground?m is it as defining as it sound on the video?

 

[DannyBoy]

been told it sounds the same outside compared to video and it sounds about the same inside aswell.

just jacked up both rear wheels seperatly spun them anf have no sound. decided to put bricks on the other three tires and turn it on to see if that made a difference. they spun to around 40kmph the tracion control light came on and there was absolutely no sound like in the video done that to both rear wheels.

could be something to do with 4Low possibly?

 

[nathand22]

I can say that when the traction control is firing it will make a noise 100% has to, even if you go onto a dirt road or grass padock and slam on the brakes you will feel the brake peddle clunk clunk and vibrate back through your foot as the ABS fires, and as the ABLS is using the same system it will do the same thing and make the same noise.

 

[DannyBoy]

I can say that when the traction control is firing it will make a noise 100% has to, even if you go onto a dirt road or grass padock and slam on the brakes you will feel the brake peddle clunk clunk and vibrate back through your foot as the ABS fires, and as the ABLS is using the same system it will do the same thing and make the same noise.

thing is tho im not braking in the video so ABS woulnt be kicking in while im on the gas

 

[nathand22]

thing is tho im not braking in the video so ABS woulnt be kicking in while im on the gas

your not understanding how the ABLS works, it uses the ABS system to work and the harder you hit the gas the more the wheels spin at different speeds the more the abs is firing to try and work the ABLS.

so bottom line is YES the ABS is working when you are on the gas

 

[DannyBoy]

ah right gotcha thanks

 

[DannyBoy]

Pretty certain I found what was causing the sound.

Took it to the inlaws place as they have a creek crossing which is dried up at the moment, got the truck stuck across it (on prupose) had a Front & Rear tire breaking traction.

Tried 4H first giving it a good amount of pedal with no noise at all, switched over to 4L and no noise again.

Had a look underneath where the tail shaft is and noticed the tail shaft has marks from it rubbing/grinding against the fuel tank bash plate!, Must only rub against when there is flex in the chassis

Going to either try and move it as far to the passanger side as I can or bend the side more so it gives it some extra room.

Photos of tail shaft etc:

https://imageshack.com/i/p711P5g4j

https://imageshack.com/i/eyKB8L7oj

https://imageshack.com/i/p9gOG6m3j

https://imageshack.com/i/iqJNQ6jWj

On the last photo you can see how it looks like it has been bouncing against it.

sorry the image coding isnt working for me for some reason

 

[nathand22]

I just wonder why it wasnt doing it in 4H and only 4LOW?

also while you were stuck could you hear the ABLS clicking trying to work?

and how long were you revving it or allowing the wheels to spin before you got off the go peddle?

 

[DannyBoy]

my guess would be not enough flex during 4H for it to rub aginst it.

couldnt notice it probably more focused on earing noise from drive line.

had the wheels spining more than once in H & L had it revving for a bit. didnt break traction then let off. i let it wind up a bit then backed off. while i reversed out of the crossing (it goes up hill) i broke traction and had no sound