Center Diff Lock Issues (on, off, or in-between)

[Heath]

My diff lock goes on and off when the lever is pressed over to the left in high or low range.
I think the light is correct when it goes on and off. Does the light work off of the linkage, or the actual diff lock?

Assuming the center diff lock does not work...
Could it be the linkage is worn out?
Could it be the actual center diff lock?

I really don't know how it works.
I just put an ARB in my rear so I am itching to use it.
I saw some stuff about spraying the linkage with lube and working it...
I already tried that...

That linkage looks like a very weak setup to begin with.
Does it work off of an electronic actuator or what?
I have no clue on where to start.
Thanks in advance for any help!

I have to make due with this t-case until I can get a replacement.
-Heath

[Scott 9835]

The light works off the diff lock when it engages it press on a switch. If the light works the dif lock is engaged.

[Roadsiderob]

The actual diff lock mechanism inside the transfercase is pretty robust. The switch for the light is actuated off of the shift fork inside the t-box. it is a spring loaded mechanism, so you can throw the lever and if the teeth arent lined up, the mechanism will spring load and then drop in when the teeth do line up. The light will come on at that point. Same thing when you disengage it. The mechanism will spring load if there is any driveline wind up holding it in place and then release as soon as it can. So the light activation and deactivation is not always immediate when moving the lever. If your light is flickering at random when engaged I would be looking for dirty switch contacts or maybe a bad bulb or a loose electrical connection. You can test diff lock operation by applying the park brake and leaving the transmission in neutral and jacking up one front wheel. With the diff lock disengaged you will be able to turn the wheel, with it engaged you will not be able to turn the wheel. You can call me at the shop later if you need more specific details.

[Heath]

Well then... I guess my problem is that my center diff lock won't stay on.
The lever wants to move right it seems, but even when I hold it to the left the light goes off (low and high).
Any suggestions on how to fix this?

I just got my ARB in the rear (which works great) and I can't try it out without the center locked.

Rob, I had not seen your post when I wrote that...
I think the diff lock starts on and comes off.
It doesn't really go back on until I push the lever over to the left.
It did work for the test, it just pops out I think.
It is not flickering at random.
It is more of an on then off thing... then I press the lever left again, then it comes on for 5 to 30 seconds sometimes a min.

Thanks very much,
I'm going to jack up the back real fast... actually the front.

[Heath]

I did the test and here is the outcome...
The problem is the linkage.
The transfer shift from right to left only moves the linkage 20% of the full distance...
I put a prybar on the lower linkage and pushed it manually (while my father sat in the truck and moved the lever all the way to the left). It had about 80% of the distance left to go into "diff locked" status.
Once I did this we tested the truck off the road and everything stayed locked. My rear ARB locker worked like a dream, spinning both rear wheels in unison on the soft mud.

Now to figure out how to fix the linkage.
Is there anything that wears out easily that is a common fix?

[Roadsiderob]

Well,
there are some plastic bushings in the linkage that can wear, the linkage itself can wear, it may be out of adjustment. I'd take a real close look at it and see where the looseness is. Take the rubber gaiter off of the transmission tunnel and remove the foam surroud for a good view of all of the linkage.

[Heath]

Thanks for the advice Rob!
I took off the hump and tweeked the pivot point on the linkage and now everything is working!!!
It was just a sloppy linkage after all.
Thanks so much for your help.