Diff-lock Trouble

[Rhett]

Another update and a kind request for any advice :

I took the Patrol to a park and activated diff-lock again, 4L and proceeded to do some circles. When doing a clockwise circle, the inner (right) rear wheel bites the ground and leaves noticeable tracks which indicate the diff-lock is engaged.

As soon as I turn to the left and do an anti-clockwise circle, the diff-lock light flashes (disengaged) and the inner rear wheel (now left) does not dig up the ground. This is puzzling to me.

I then did the above but in reverse. When doing a clockwise circle in reverse, (left rear still on the inside) the diff-lock engages (solid light on the dash) and it begins digging up the ground. When I did a reverse circle anti-clockwise (now right rear on the inside), the diff-lock disengages again (flashing on the dash) and the wheel does not dig up the ground.

There is no noticeable noise coming from the rear diff. Anyone able to give any advice on this?

[Michael]

Sounds like a mechanical problem and something to do with the actual diff lock mechanism.

But I might be wrong

[Rhett]

Thanks Michael, I believe you are probably correct

[ricster]

I've never heard of this, but I can only think that there is maybe some rounding maybe on the dog tooth that somehow allows it to disengage when the side shafts are under different loads depending on the turn direction. ... Can you hear any clicking noise from the diff when its not locking up?

Ok I don't know much about difflocks at all, so this may be silly comment. If the vacuum is not what it should be, could that allow the dog clutch to engage but just not engage with sufficient force/power to stay fully engaged, allowing the (possibly worn) dog tooth to slip out? If this is the case then would that mean that the vacuum pump is worn and/or a leaky pipe almost anywhere in the pipe system from the vacuum pump to the black canisters to the solenoids in the engine bay and the pipes leading all the way to the back diff?

[Bruin Beer]

Cedric,
My money would also be worn dog tooth on one side.
My feeling is that if it was a vacuum problem this is a constant irrespective of the direction of turning.
Sound like a periscope inspection to confirm or eliminate this one before doing to much stripping.
Keep us informed.
Bruin Beer

[Rhett]

Thank you! Yes I will have to do some inspection to see what is happening. Perhaps I will pop in to RDG and ask if they can assess it for me.

Will keep you informed!

[Bruin Beer]

Rhett,
What I meant was a bore scope inspection. Just realised my mistake but guess you got the idea.
This should be possible through the diff filler plug.
All the best and keep us posted.
There is always something for all of us to learn.
Thank you.
Riaan

[Rhett]

Haha yes thanks Riaan, I knew what you meant even though I didn't know you were wrong.
I called Rex Diff and Gearbox now. The techie says I need to pull the vacuum pipe off the actuator on the diff, and see if anything happens, otherwise it might be faulty fork. To me this doesn't sound like it could be the problem, but worth a try, Otherwise off to the mechanics I go.

[Wilkie]

Hi Rhett...does the ABS light flash when you engage 4x4..??

[Rhett]

Hi Wilkie

Yes it does, constant flashing.