Hilux 4x4 Forum

Howdy,

Ive got a 2012 hilux D4D with a set of ARB air lockers in the front and rear. the person who had been driving it always drove around with the air lockers engaged but in 2wd for the most part. now it makes this clicking noise all the time while driving. i have checked the cv shafts and i have checked the front prop shaft and there is no slop in either so i dont belive them to be the problem. i am wondering if there has been damage done to the air locker itself or maybe that shaft thing that comes out the side twords the right side of the vehicle (if your sitting in it) or maybe the input shaft of the diff itself is damaged? I have not been able to replicate the sound with the vehicle off the ground which is why I'm asking you all for help. the confusing part for me is that the air locker on the front still works as it should just the sound gets much louder when it is in 4WD. ARB builds some quality stuff but im not sure if even they can handle that kind of abuse.

to note: I think its the front diff itself but just thought i would throw this out there to see if any of you had the same or a similar issue.

thanks

Hi and welcome Andrew.

From what you say, I'm assuming that the model is and independent front suspension type with an ADD (automatic diff decoupler) on the front diff. Typically the ADD will disengage the diff when not in low range which should have avoided damage, but it seems there is no way of knowing how or if the vehicle was abused.

I also noticed with your registration application that although you give your location as Washington USA, your ISP was located in a semi desert area, and if that is where you are indeed located, are we talking about loose gravel dirt roads and tracks or are we talking about hard driving surfaces like asphalt, hard packed ground or rocks? Surely the rear diff would have suffered damage if the rear locker was also always engaged.

Soft forgiving surfaces would perhaps have saved the diffs from damage.

Going on my assumptions that you're in a semi desert area and that the vehicle has been used on forgiving gravel and that you're talking about the front diff only, it would account for the diff to appear to be still working. In that case the ticking could simply be a faulty ADD. Perhaps it's just gummed up with all the dusty conditions that the vehicle has been used in, and just needs a cleaning.

Personally I am not familiar with the workings of the ADD but there is a thread or two here that cover the removal and service of the unit. Just do a search for it using keywords like "front diff ADD", "front diff ticking" etc.

Good luck getting it sorted and perhaps some of the other members can add some more useful insight.

Mud Dog,

Thank you for that information. I will look up the automatic diff decoupler. would that be an item replaced by the Air Locker since that is basically an entire differential replacement? I do believe that there has been some damage done to the rear diff as well but its not as bad as the front. I will update if that solves the issue.

You wrote:would that be an item replaced by the Air Locker since that is basically an entire differential replacement?

No. If your model is of the type that I suspect with an ADD, then the function of the ADD is to disengage the diff when not required, thus reducing the amount of friction / drag and improving fuel economy as well as wear to the diff itself. These models don't have hub locks, so the half-shafts still turn but don't drive the crown wheel & pinion in the diff when the ADD is disengaged. From the power side, the prop-shaft only engages when the transfer box is activated (4WD).

The ARB diff lock will just lock up the spider gears in the diff which then doesn't allow a differential of rotation between the two half-shafts.

Hope that helps.