Thread: D4 CV Joint Failure ????

Originally Posted by BMKal

Possibly - but the diff unlocks immediately you shut the engine off, so this "benefit" is short lived.

I also didn't have the EPB applied for that test, so not sure if that will influence it's centre diff locking behaviour. I will try to do another one and use the EPB this time.

Originally Posted by BMKal

Possibly - but the diff unlocks immediately you shut the engine off, so this "benefit" is short lived.

On hill, for hill starts etc... and as part of the drive through take off etc.

Originally Posted by BMKal

Thanks again for everyone's help on this. It would appear that the problem is now fixed, and I may have saved myself quite a few dollars in transporting the vehicle to Perth and having it repaired there.

The Gap IID tool has definitely paid for itself (as has the D4 workshop manual that I bought from Dave quite some time ago). Having a son who is a diesel fitter / mechanic and who is not afraid to pull things apart / play with settings / use diagnostic tools etc is also a big help.

So, today we had the vehicle up in the air. Checked all electrical connections around the transfer case and could see no sign of water ingress / dirty terminals / corrosion anywhere. In fact, for a vehicle with over 120,000km on the clock, the whole transfer case area still looks like brand new. Checked transfer case oil level and condition - level was exactly where it should be and the oil looked very clean and like "new". No sign at all of water in the oil.

Discovered that with the engine off, you could turn the front prop shaft about a quarter of a turn independently of the rear prop shaft, which suggested that the centre diff was not "locked" with the engine turned off. As soon as engine was started, you could hear a distinctive "clunk" from under the vehicle which turned out to be the transfer case clutch solenoid activating / engaging (I could not hear this from inside the vehicle). As soon as this happened, the centre diff was locked, even though not showing this on the main screen display or anywhere else. You could not turn the front prop shaft at all once this clutch had engaged. Shut off the engine, and shortly afterwards, could hear a very distinctive "clunk" from under the vehicle (I had noticed this "new" sound over the past few days). This was the clutch solenoid de-activating / disengaging. As soon as this had happened, you could again turn the front prop shaft about a quarter of a turn independently of the rear shaft.

So - pulled the electrical connection from the clutch solenoid and started the engine - the solenoid did not activate and you could still turn the front prop shaft. Lowered the vehicle down off the axle stands and took it for a test drive. No more shuddering / grabbing / scary noises. Only a "Gearbox Fault" showing on the dash. Worst case scenario - I could drive the vehicle down to Perth like this if necessary, with no centre diff lock available - but this would only be a last resort.

Next, re-connected the electrical connection to the clutch solenoid, plugged in the Gap IID tool, checked all faults and cleared them, then ran both the Transfer Case Clutch Calibration and the Position or Range Sensor Calibration routines as per the instructions in the Gap IID manual. Took vehicle for a test drive and everything working as it should be. Stuck it into low range / rock crawl, observed indication on dash screen that centre diff was "locked", drove vehicle in a tight circle and observed indication of centre diff locking and unlocking as it should do when diff "wind-up" occurred. Then returned all settings to "normal" and observed on screen that centre diff had unlocked. Another test drive to confirm that everything is working as it should be - and I am now sitting down relaxing and enjoying a scotch and dry .................

So it appears that something was sending a signal to the clutch as soon as the engine started, and the centre diff lock was engaging. When the engine was switched off, the diff lock would dis-engage. Exactly what was causing this signal to be sent to the clutch solenoid is a mystery, but I can only assume that the Position or Range Sensor had somehow gone out of calibration and was causing the problem. What caused this to happen is anybody's guess - but at least it's comforting to know that with the Gap IID tool, the workshop manual and the assistance of those with knowledge on here, it's possible to fix these things yourself. especially when the closest dealership or independent workshop I would trust with the vehicle is over 600km away.

Digging up an old thread as i'm just after an update. BMKal, did this ever reoccur? I'm having the same issue, although mine's only temporarily staying unlocked after running the two calibrations. It's locking itself again after a short drive.
I'm considering paying for the software update, as it's out of date. Although seeing as I had the TC replaced in 2016 you'd think they would have done it. Is there any chance replacing a TC with a new one and not updating the algorithms could destroy a TC within 40 000 kms? There's no signs of an oil leak from the seals...

Positive side to this issue is both my front and rear diffs definitely still have LSD, after 220k kms it's chirping wheels in any car park or slow/tight corner like a RWD falcon with a mini spool

Hasn't happened again, but the car has had very little use since this problem was encountered. I'm back working again full time at the moment and have a company vehicle, so the Disco rarely ventures out these days.

To be honest, I'm seriously considering replacing it with a dual cab ute - have started looking at available options.

Update : Got it out of the shed today (Sunday). Gave it a good wash and took it for a long run. No problems / faults at all. After driving a HiLux for the past 6 months or so, I had forgotten how good this thing is to drive. Am now amongst the ranks of the semi-retired / unemployed again, so no more company vehicle. Will have to make a decision on whether or not to keep the Disco - but a ute is looking very attractive at the moment.

Originally Posted by BMKal

Hasn't happened again, but the car has had very little use since this problem was encountered. I'm back working again full time at the moment and have a company vehicle, so the Disco rarely ventures out these days.

To be honest, I'm seriously considering replacing it with a dual cab ute - have started looking at available options.

Update : Got it out of the shed today (Sunday). Gave it a good wash and took it for a long run. No problems / faults at all. After driving a HiLux for the past 6 months or so, I had forgotten how good this thing is to drive. Am now amongst the ranks of the semi-retired / unemployed again, so no more company vehicle. Will have to make a decision on whether or not to keep the Disco - but a ute is looking very attractive at the moment.

Yes I'm considering the same, trading in for something of lesser value (dual cabs can be had for $15000) I've gone from high income earner to uni student so one extreme to the next too. It will be a shame if it has to go, they really are the most versatile vehicles on the market.

Hmm, i'll have to try the Transfer Case ECU update on mine as a last ditch attempt.

Thanks for the update btw, I just found it.

Russ

Originally Posted by BMKal

Will have to make a decision on whether or not to keep the Disco - but a ute is looking very attractive at the moment.

Mechanophilia 🤪