Automatic going into Low Range but not locking centre diff, Intermittent.

[AustralianSon338]

Hi all, has anyone had this kind of fault before?

I had driven down a range including one ridiculously steep and shailey hill and then when I got to the bottom of it the Bloody Difflock light turned out. Initially I was thinking that the dashlight had just blown or something but quickly realised as I began driving up this hill and the front wheels began to spin that the centre diff was no longer locked. I could'nt get it to lock and as such after about 6 goes I resigned myself to the fact that I had to flog the shit out my truck to get up this bloody hill. Poor thing was limiting at 5300 RPM or so. I normally just like crawling at 2400 RPM type thing as Im a nancy boy driver. Not really I'm just not a fan of flogging them to get up hills.
So after getting up the hill I continued shooting and had turned the truck off for a shot and then about 10 minutes later, started the truck back up and hey presto the bloody difflock light was on!

I Was moving it this morning for a wash and thought I would do a quick check to see if it was still failing and as I moved the lever to low range the difflock light came on but then turned off almost immediately and I could hear the relay under the dash clicking on and off. My guess is possibly a switch thats utilised with the low range lever playing up. I know absolutely nothing about these trucks boys but am a diesel fitter so speak as plainly as possibly if you have the info. Very keen to fix this issue as the truck is Fkn useless as a 4WD without the centre lock. Bloody wheel spinning everywhere! Its a Petrol 4.5L GXL.

Thanks in advance!

 

[Chris]

Not sure quite what is happening there, but the diff lock as you rightly point out is electrically driven. So it is entirely possible to be in low but not locked unlike a Colorado which is a mechanical actuator (OK than can have issues, but move on...).
The motors can have issues and is a probable cause but there are other components in there too such as the lock detection plunger, the 4x4 brain box and the loom / connectors. I haven't heard of this before so I can't give you an exact diagnosis. Having the dashboard lock button fitted would make it a little easier to hear if the motor is running under the car.

Chris

 

[AustralianSon338]

Yep it also has the Dashboard lock button Chris. I can press that in high range to lock the diff but in Low it's supposed to lock automatically. When the Lock is working in Low range, the button for high range works aswell. When its not working in low than the button wont work for high either. I was hoping that this was going to be a common issue but I may have to invest in a Factory manual I think.

Cheers mate.