[henno]

Finally installed my free wheeling hubs yesterday and after deciding to go for a bit of a shake-down run and make sure everything is operational I noticed my 4wd light not coming on. After following fordem's great thread here: viewtopic.php?f=17&t=19613 and with Mrs Henno checking for the 4wd light turning on and off I have chased the pressure issue all of the way through the pump outlet until it reaches the back of the diff. If I put my finger over the end of the hose there the light turns straight on (I didn't test the actual pressure, but there is heaps of air coming out and the light turns on almost instantaneously.

So the issue is clearly to do with the actuator in my diff. My only question is why would this issue coincide with the installation of the free wheeling hubs? The only other 'maintenance' I did yesterday was hit the underside with a blast of the high pressure hose like I always do to dislodge sand and mud and what not, so my initial thoughts where I simply dislodged a wire or a hose or something. Now that seems to not be the case at all, and what I thought would be a 2 minute fix now has me worried.

Maybe the actuator died on my trip at Straddie? I can't remember ever checking the 4wd light - who does, I am clever enough to know where the transfer stick is meant to be - so maybe I was driving around in 2wd most/all of the time? (Might explain why I thought the KL71's were so rubbish in the sand. )

Is there any AZ good tech to troubleshoot this or do I need to deal with the fact that I am going to have no 4wd until I get this sorted (I really don't want to spend a dollar on the glass diff). Or should I waste more money and buy a gauge to make sure there is 5-8psi coming out the back of the pump?

Thanks in advance.

[ozzycouch]

Not worrying about the light issue, have you jacked it up and checked that it's getting drive to the front wheels in 4x4?
Pending what's spinning, (Hubs locked/unlocked) it might give more insight to the problem, or confirm is wrong.

[henno]

I did that... of sorts. I couldn't get the rear stands high enough in a safe manner for my liking (call me old), but with both fronts off the ground, the engine running, hubs locked and the transfer case in 4 high or 4 low I would turn one or both of the front wheels without any resistance whatsoever. With an open diff, I am not sure this tells me a lot... but I would think that with the rear tyres planted, gearbox in neutral, transfer case in 4wd and hubs locked, I wouldn't be able to freely spin the front wheels by hand if the front diff actuator was doing its thing?

[ozzycouch]

If the front diff was engaged and working, at least the wheel on the other side of the car should be spinning the opposite way.
It does sound like the actuator has given up. I would check to see if it's leaking.
Any way you can rig up something like a bike pump with a gauge and see how quickly it looses pressure?

[just_cruizin]

Scrawny did some work on one recently where the bellow that engages the diff had let go. Sounded like a bugger of a thing to replace.

[watermouse]

just_cruizin wrote:

Sounded like a bugger of a thing to replace.

I would agree with that.

It could be that the hose from the actuator to the inside spigot has come loose or split which wouldn't be so complicated to replace but the actuator is center out and a bearing off.
If that is the issue I have a spare one on the bench I can give you if you could be arsed replacing it. My recommendation would be to ditch it altogether if you can find a vit center or you want to weld the one you have.

http://www.auszookers.com/forum/viewtopic.php?f=5&t=47843

[henno]

If this diff has to come out, it won't be this diff that'll be going back in.

[Scrawny]

Yeah, wasn't a real fun job but now that I've done one it wouldn't take as long to do another one.

The acutuator is like a rubber balloon that blows up, the one I replaced had simply burst. If you want a simple fix then just replace it.

[henno]

Is there an easy way to check without pulling the centre? I was thinking of attaching a pump and pressure gauge to the inlet tube and pressurising to 5-8psi and seeing if anything happens? (i.e. see if the light comes on at all, and then try spinning the front wheels while off the ground to check that the diff is engaged.)

[Scrawny]

The light will only come on when it builds up and maintains pressure at the pump. If you're getting pressure at the end of the hose, where it connects to diff, then your only option is to pull the centre out. I'd say the actuator has burst.