The dreaded flashing c/diff light - but wait its not the usual causes

[tmoreland]

Hi Guys, i know this topic had been done to death and trust me i have read all posts and am still at a loss.
Brife history, NM 3.5L manual, hassel free for years! until some months ago after a trip to Stockton i had the amber flashing ligh on the centre diff flashing. No prod, take it and get scanned it shows the #2 solenoid is faulty, so out it come. The next week i was off someware and locked the diff and then straight away the flashing amber light is back.
So off i go again and this time select to replace all 5 solenoids in 1 hit to elimate the chance of another failing/sticking.
Some time later on another occasion when i locked the diff again the same amber flashing light apears... Not happy Jan, so its back to the shop. This scan reveals no electrical or solonoid faults and as the box is getting on, i'm told its in the transfer box so out it comes, and is rebuilt, back in it goes.
Brings us to today:
I had been going through the gears trying to loosen the up so to speak and until today did not have a chance to get out and try the car.
Working through the gears locally everything appeared to be fine so I headed up to the Watagans this afternoon.
As you can see in the video links below it did not go to well!
Everything was fine for about 10minuits going through 4H, 4Hlc so I decided to take a side track and try out low range. Virtual straight away a little glitch started with all 4 green lights flashing under acceleration, but it still engaged gear intermittently. Trying the old back and forth to get it to engage ventrally failed and after about another 10 minutes all gears would not engage with centre diff light flashing...
I knew it would be hard to explain and I had a gut feeling it would happen so I took a vid on my phone hoping it would help explain.

This video shows the car working through the gears and all working fine! I am in 4LLC heading up a slight grade and it starts to play up, i can make it engage gear by rolling back and moving forth. This fails after a few attempts, and eventually I get an error in all gears and I end up with only 2wd.... Vid: http://youtu.be/eUshpunfeVA
When I went to the Simpson trip the same thing happened after about 25mins and I ended the trip as I do in this vid, in 2wd

This vid shows the car in its current state, all is fine in 2wd and now as soon as you engage any other gear you get the dreaded flashing centre diff light... Vid: http://youtu.be/RP0Gvq0v-4o

Any help or tests you can suggest I try to diagnose this issue would be appreciated.

Thanks

[adrian]

Could it be a 4wd ECU problem?

Adrian

[tmoreland]

Hi adrian, i thinking along those lines, but when the auto electrician scans it everything shows up as fine. Do you know if there is a phycical test or how to test without relying on the scanning?

[adrian]

No but after reading a lot I believe that the best way to test is to swap it with a known good working ECU and see if that improves things. I read somewhere that the 4wd ECU doesn't always give error codes. One other thing is if the radio as been swapped then maybe a connector as been dislodged or a wire as been broken.
By the way I am a new owner of a Pajero so before taking my word find an expert

Adrian

[Aussie_Dan]

Have you checked the diaphragm actuator that is bolted to the rear side of the front diff, to make sure it is moving when it should?
There is also an electrical switch on the front diff that will change state (sorry, not sure whether it opens or closes the circuit) when the actuator moves and the front left driveshaft is connected to the diff.
I am pretty sure that the transfer case will not engage the front tailshaft until the ECU has received the signal that the front left driveshaft is already engaged.
Perhaps this is the next area that you should be investigating?
Dan.

[tmoreland]

Thanks guys, i'm joing to check the actuator, and do as suggested in another post which was to lift 1 front wheel with the car running engage 4LLC and check if its actually engaged and the car should stall.

[dolphin]

the best way to check the front diff actuator is to firstly pull the boot away from the actuator rod then try going into 4 x4 drive with a helper watching to see if this rod moves in or out when 4 x 4 is selected.

[adrian]

Tmoreland can you let us know how you get on?

Adrian