Overcooked the 4x4?

[solidpro]

Hi

Okay, I have a '94 Gen2 3.0 TD. I only really have to use the 4x4 a few times a year as we all know these should never be in 4wd on fixed surfaces. So sometimes I appreciate these things hardly get used and you never know when something might go amiss. Well I noticed that when I did occasionally use it, by pressing the 4wd button on the side of the small gearstick, it wouldn't de-select like it used to. I know there is a delay but am used to deselecting 4wd on the button and then a few seconds later, the 4x4 light going out on the dash and 'feeling' the transmission change. This wasn't happening. It would randomly disengage after anything between 20 seconds and 2 minutes.

So this caused a problem - when I was using it in the snow, I would usually turn the 4x4 off once I hit 'treated' roads that didn't have loose surfaces. Of course, I couldn't get the 4x4 to disengage and so I drove it about 8-10 miles on and off hard surfaces IN 4x4 mode. Suddenly a really burnt oil smell is coming in the cab and lots of smoke from under the car - at the front, directly under the engine, where I would expect the front wheel drive transmission to be..... I managed to get the 4x4 disengaged and the problem stops.

When I got to my destination, you could see and hear under the engine that it was cooked - with oil leaking onto the road.

I did 'test' the 4x4 again afterwards, when I hit thick snow, and it disengaged easily and did seem to function as normal.

So I guess the point I am slowly getting to is:

1) Did I just overcook it and ..... get away with it? Since then she's been fine - no oil leaks and works perfectly in RWD.
2) Why does it not always disengage when it should?
3) If I can't get it to disengage, is there a quick workaround - like removing a fuse - say if I don't want to drive it further without disengaging the 4x4?

I just spent £1000 on it with new full exhaust, brakes overhaul, cambelt, MOT and so on, so I want to see her last, but new 4x4 just wouldn't be worth it! She's on 220000km and otherwise still going strong.

Thanks

[shokenore]

Seeing as you have not yet had a reply.

1) Did I just overcook it and ..... get away with it? Since then she's been fine - no oil leaks and works perfectly in RWD.

What do you mean overcook it?

The oil leaks could be a major concern but you will need to be more specific as to what type and quantity of oil you had lost.

As far as I am aware any oil loss should be a cause for concern,you need to check your oil levels asap.
Engine oil .
ATF.
and
Front Diff.

"smoke and oil leaking out onto the road "do not bode well.

[stormforce]

You need to really test the 4wd system once a month if its not used regulary.You may of caused what they call transmission wind up by driving it on solid ground.
If it is working ok now you may not have caused major damage to the diff but you have probably blown the seals.Get it checked out before using it again.
It may work out cheaper and quicker to just get a 2nd hand diff from a breaker.A couple of hours and you'll have it changed

[TonyN]

I don't think you can 'cook' the 4wd, it'll either break or it won't.

It's just a diff and a propshaft.

I have been told that the rear plug on the front diff isd actually a temp cut so if the front diff does get hot it'll dissconnect 4wd anyway, but I've never checked this.

There is lots you can check to make it work properly, especially the vacuum hoses for splits and the ADD mech to make sure its free, then check the 4wd solonoid on the back of the t/case.

Old worn componants will make it sticky, some truck you have to stop and just back up a little to get it out.

If you want a short cut fit manual hubs and lock the ADD actuator on the front diff on, you won't have the smooth shift on the fly, but it'll still work with a bit of a clunk.
But its no big deal to lock the hubs in the morning if you're going to need 4wd, then just pull up and select 4wd like normal and carry on.

Where did the oil come from? You must have had to top something up if it was that bad?

I've had several trucks driven to me on the road with 4wd locked on, its no fun to go round tight corners, but they've all got here, and been repaired with nothing broken from doing it.

[Spike78]

My 4x4 stuck on for about 3mins after i turned it off about 3weeks later went up my mates farm used the 4x4 and turned off as soon as i pressed button tried it few times up there and hasn't stuck on since.
Hopefully jest a bit of dirt kept it on.