Stuck on diff lock?

Technical questions and answers
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firemanshort
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Stuck on diff lock?

Post by firemanshort »

My center diff lock plungers moves back and forth and the indicator light on the dash turns on and off as it should with the movement of the center diff lock switch. But.... the diff is still locked no matter what. I have jacked the wheels up and confirmed positive lock between the different axles (even with the diff lock light turned off and indicating that the diff lock is disengaged).

I have a Detroit auto locker in the rear end and driving on the firm grip pavement with the truck still in diff lock is causing all sorts of problems.

Has anyone else experienced a stuck diff lock before?
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map1275
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Re: Stuck on diff lock?

Post by map1275 »

Look in your parts book. It will either be something simple like a break in the selector mechanism or otherwise an internal issue with the diff. Both are accessible/repairable in car.
disco2hse
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Re: Stuck on diff lock?

Post by disco2hse »

I had a number of CDL issues and yes, that was one (actually intermittent engaging/not engaging). It was this that I describe below. Also, I had a corroded earth wire so the CDL would be engaged but no light on.

The light is a simple earthed connection. When the CDL plunger engages, it is earthed and vice versa.

So, if the plunger is disengaging but CDL is still locked, then it is likely to be somewhere around the selector fork. Probably it has come loose or broken/worn.

V8 Supplement, page 37.29.19.

Good luck.

Oh, and as you know. Don't drive on solid ground with the CDL engaged. You'll get wound up.
Alan

1983 ex-army FFR 109 Stage 1
2005 Disco 2 HSE TD5
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firemanshort
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Re: Stuck on diff lock?

Post by firemanshort »

Yes - plunger moves - light goes on an off. I think it is inside the centre-diff.

What I really need is a few days off where I can catch up on household chores and make dedicated time to take a crack at this with some wrenches.

I have been on solid business travel for two week. It pays the Land Rover bills but robs me of my time.
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disco2hse
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Re: Stuck on diff lock?

Post by disco2hse »

Taking the fork out is not that hard and you'll see quickly where the problem is. Pulling the driver's seat and centre console out makes access quite easy.

I know how it is with getting time.
Alan

1983 ex-army FFR 109 Stage 1
2005 Disco 2 HSE TD5
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Geoff
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Re: Stuck on diff lock?

Post by Geoff »

The diff lock on my second Stage 1 wasn't working when I bought it (wouldn't engage) Inspection revealed the vacuum actuator to be corroded and holed (so no vacuum) and no shield, which may have contributed to the corrosion. Replaced both. Turned out the actual diff lock mechanism had also been incorrectly reassembled by the garage the previous owner had taken it to to fix an oil leak (paperwork said they'd 'road tested' it after putting in a new seal and 'all working'! - obviously they hadn't tested it off road) - but the holed actuator wouldn't have helped, so worth checking you have an actual vacuum there.
2 1981 Stage One 109 V8 SWs
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firemanshort
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Re: Stuck on diff lock?

Post by firemanshort »

I was finally able to find some time to work on this. I pulled the shifting mechanism and all is good. I am able to peek (barely) inside the shifting area of the centre diff and I can see the shifting collar moves freely back and forth but the front and rear shafts are fixed together (rotate together).

So the problem is not in the shifting but in the centre diff itself, I suspect. I am now off to remove the entire front output shaft housing and dig deeper into this mess. :? (The repair manual really is lacking in detail here.. .but I will figure this out....)
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disco2hse
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Re: Stuck on diff lock?

Post by disco2hse »

Rats. We always hope for an easy fix :/

I presume you are looking at the V8 Supplement pages 37-24 to 37-33.
Alan

1983 ex-army FFR 109 Stage 1
2005 Disco 2 HSE TD5
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firemanshort
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Re: Stuck on diff lock?

Post by firemanshort »

Those are the pages that I am staring at......
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map1275
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Re: Stuck on diff lock?

Post by map1275 »

The manual doesn't cover every step but the key points are there. From memory the diff exits via the rear output. Otherwise try a Haynes manual, they sometimes offer a little more detail.
disco2hse
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Re: Stuck on diff lock?

Post by disco2hse »

There was an LT95 service manual floating around the ether a while back but I haven't been able to find it. Google has a very short memory these days and prefers to throw paid advertising and pinterest at me (I don't have a pintrest account :? ).

EDIT:
Spoke too soon, try this http://www.landroverweb.com/Pdf-files/M ... nual-3.pdf
Alan

1983 ex-army FFR 109 Stage 1
2005 Disco 2 HSE TD5
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firemanshort
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Re: Stuck on diff lock?

Post by firemanshort »

Nice link to the transmission manual. It should prove helpful.

I downloaded a photo I took of the oil pan when I drained the oil from the gearbox. The oil pan was brand new from the store - so this was the first oil to every get dumped in it. The results confirm what I already knew. :(

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Firemanshort
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disco2hse
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Re: Stuck on diff lock?

Post by disco2hse »

Shame it's not gold :?
Alan

1983 ex-army FFR 109 Stage 1
2005 Disco 2 HSE TD5
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firemanshort
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Joined: Fri Feb 10, 2006 2:42 pm
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Re: Stuck on diff lock?

Post by firemanshort »

Finally.... Finally, I was able to find some time to work on my truck.

I took out the center differential assembly and bits like this started to fall out. I think this confirms that the planetary gears and shaft have been damaged.

Image

The whole center differential is enclosed inside a gear assembly - more photos to come. So I have not seen the whole of the damage but I can hear more parts rattling around inside of it. It is enough to say that parts are broken. I swapped out an entire center differential assembly from a parts transmission I had and put my truck all back together. I was able to do all of this without taking out the gear box and working with it in place.

My truck appears to be working as intended now - but I have not had time to take an extensive test drive. I found a broken spring shackle u-bolt that I need to replace before I take it too far down the road.
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Firemanshort
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disco2hse
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Re: Stuck on diff lock?

Post by disco2hse »

Yeah, that'll do it. :shock:
Alan

1983 ex-army FFR 109 Stage 1
2005 Disco 2 HSE TD5
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