Transfer 2 to 4wd by itself - lights flashing

[Bricktor]

Hi all,
My NH auto has a habit of jumping into 4WD by itself. The Super Select flashing the front wheels indicate they are not set properly, but I know it is in 4WD as I have a bad bearing in the front Diff and it starts howling. Moving the lever switches it into the locked All wheel drive position. Moving it back does not change it, but the super select lights start flashing again. It eventually goes back into 2WD by itself. If on a longish journey it will stay in 2 wheel drive, but if I stop & have to reverse or such, it will intermittently change into 4WD again wlth the super select flashing.
Can anybody shed some light on the problem?

[fgin]

I've read that when the vacuum solenoids fail the front hubs get locked. I might be wrong but have a look at this thread which I started recently.

http://www2.pajeroclub.com.au/forum/...ad.php?t=35407

Hope it helps.

[Bricktor]

Thanks fgin,
Read the threads, this could be the problem.

[fgin]

Thanks fgin,
Read the threads, this could be the problem.

Great! get some wd40 and try what Pauly Faulkner recommended. It has worked for me.

[NFT5]

Yep. Not uncommon. Sticky solenoids are usual culprit. Have to remember that default is 4WD and vacuum holds it in 2WD (front axle) so if vacuum isn't being applied then you'll get the issues you described or similar.

Clean the solenoids and check all vacuum hoses - they're getting a bit old in an NH and replacement is cheap and easy.

[Pauly Faulkner]

Good to see that still working for you fgin

If the lever itself is not jumping out and it's just the lights coming on and a howling noise then I'd be getting onto lubing up the actuator shaft and checking them solenoids. Also check for vacuum leaks(i.e perished hoses) on the solenoid lines. The actuator has a spring to default the front diff freewheel clutch to engage(blue solenoid is just to help it in and help hold it in), if partial vacuum is lost it can half engage/not engage properly and you get all sorts of symptoms like howling and grinding.
Also if you have a diff issue like the axle bearing(located just behind the flange where drivers side cv bolts onto) it will obviously tell you when the freewheel clutch is engaged, along with the flashing lights.If it only howls in 4wd(freewheel clutch engaged) then you might wanna check this bearing out by seeing how much play is at the flange I just mentioned or even just pop it out and check it out.

[Bricktor]

Lights Flahing Fixed

Thanks to all who posted a response. It was a faulty Solenoid. The yellow dot one. Got one from the wreckers. I have both Solenoids on order from MB. Will replace them both when they turn up.
It all makes sense when it finally dawned on me that the default is always 4WD. When selecting 2WD it is done through the ECU to the Solenoids to the Accumulator - Activator -Activator Shaft - Free Wheel Switch. Every mechanic I spoke to, wanted big dollars to try to find the problem in the Transfer case. All is well now. Minimum cost & I can do the job myself.
Cheers