Factory diff lock y61 facelift gu help

[Ham Solo]

Afternoon/Morning Folks,

I am having a new issue with my trol. My rear difflock would not engage whilst off road the other day (light just stayed flashing...in 4l below 7kmh) so I had a look at the solenoid on the bulkhead and it has power at each terminal (changes which one with switch as I assume is correct), however the vacuum I feel on either of the front pipes is barely noticeable but I have no clue how much suction there should be...enough to feel very easily i would imagine rather than this tiny amount i do have.

This is obviously annoying but not so much a "problem" I couldn't temporarily live with, however, today I get in the truck in normal 2wd use and as I pull out of my drive slowly, the diff lock light starts flashing AND then there is a binding feeling at the rear along with an obvious heavy driveline clunk which suggests to me the difflock was randomly trying to engage. I thought the ecu for the diff lock prevent it from even trying to engage when in 2wd?

It did the same on the way home too so now I am thinking it is pretty sketchy to drive!

Any help appreciated?

p.s. I have had the rear up to see if the diff lock is actually on but rear wheels turn opposite directions when spun so I assume it is off as it should be. The vac lines look pretty fresh as do the clamps...

[Ham Solo]

Also, is there a way to temporarily disconnect it so it is locked off and cant try and engage? I kind of need a vehicle to get about whilst this gets fixed

[jff45]

I think the factory diff lock needs vacuum at the diaphragm to hold it out otherwise it could engage with vibration, etc.

[Ham Solo]

That seems like a bonkers design! Thanks for the input, I am going to whip off the solenoids today and see if i can clean them up and bench test them

[jff45]

Well it uses vacuum to engage and vacuum to disengage. There are other types of vacuum solenoids that can be used as replacements.

[stevemc181]

If it is the solenoid thats buggered, replace it with a Mac solenoid as pictured below. Any decent pneumatics shop should be able to get one in, or patrolapart has them in a kit. https://patrolapart.com.au/product/n...t-mac-solenoid

[Ham Solo]

If it needs constant vacuum to keep it switch off then that must mean it switches on each time the engine is switched off?

Also, if anyone has any other alternatives to that MAC one I'd be interested in hearing as that is pricey and I can;t find it in the UK either

[stevemc181]

Have you checked the vaccum at the diff end? It might be a case of a leaking airline between the solenoid and the diff. The switch at the diff end is also known to fail, I can't find the thread that discusses this issue unfortunately, but I'm pretty sure the switch can be removed and cleaned and a new o ring put in. Worth a look anyway.

[Ham Solo]

Thank you, I will have another look at the manual diagrams