Broken or Missing Diff Lock 1996 Disco Auto

Ok I have been meaning to sort this one before the snow arrived but as the snow is falling around me I fear I may be too late!

If I put it into diff lock either high or low and drive the light dosn't come on. And there is no squeek or squeeal from my tyres (It drives the same as if its in unlock)

I jacked one wheel up and when in park (P) the wheel has a bit of play, when in neutural (N) it spins freely forwards and back and when in drive (D) it spins forwards.

Should I have locked the diff and driven it a bit first to let it engage? Or is it ok to lock it when one wheel is off the ground?


The problem is the it is is a Auto Commercial and I am not sure if it was Auto when it left the factory or if someone swoped it at a later stage. If this is the case they may have left a bit of the system out!

It drives in both sets of transfer box (ie High, Low + High locked, low locked) just there seems to be no lock.

I have another that simply refuses to move over to the locked positon as it is seized so this dosnt seem to be the problem.

I am not too sure if the parts are missing in the transfer box would it still be able to drive in the locked position with out activating the diff lock or would it just not drive at all?

Thinking about poping it over to Simonites or a main dealer to let them look at it. But just wanted to know the right way to test it with and Auto box.

Just spoken to a guy who was able to confirm off the VIN that it left the factory as an Auto so my guess is that something has gone wrong with it....

I will test the dash bulb as thats something I can do!

Any other Ideas?

Whether or not it was an auto when you left the factory is irrelevant to whether the diff lock works. If it isn't working or appears not to be there are three (at least) possibilities;
1) the bulb has blown - test by removing wires from switch, short them together and turn ignition on - bulb should light
2) the switch isn't working - remove switch, press plunger in with ignition on, get assistant to tell you if bulb lights
3) the linkage isn't working properly when you move the lever - you are on the right lines with jacking one wheel up and seeing what if it turns - someone will correct me if its wrong, but I think with the box in neutral if the diff lock is working you shouldn't be able to turn the wheel

My line of thinking was that if it was made to be an Auto they may have missed or taken the link out to get round a problem.

However now I know it left the factory as an Auto there is a high chance that the box and transferbox have never left the car hence it been something that has failed on the system.

I could understand if it was seized like the other one and would not move to the diff lock high and low position. However if freely moves over and will drive in that position just not lock the diff.

Ok just read another 101 threads about seized diffs..... And still nothing!

I managed to find a photo of the linkages so I will not try and look to make sure 1 they are there and 2 the are all WD40ed.

Problem is that the stick moves to the left locked position and will go into high or low on both sides (Locked and unlocked) It moves free with 3 finger action! Not as good as some with 1 finger but not needing Superman to move it.

It is like the internal push rod is not there meaning the stick moves but no locking takes place! Or maybe (Still not see how it fully works) a braket has come off and I am pushing the lot but not causing it to push the outer rods?

Anyone able to tell me where the light switch is so I can test it, a photo would be spot on.

The switch for the light is on top of the transfer box, you need to get under there with a torch and a mirror...
While you are under there get someone to move the lever and watch what happens

And once you're sure the linkage is working, try sticking it into diff lock whilst cornering at modest speed... even with the selector working the internals can get stuck in place if not used. Mine came unstuck at 60mph whilst thinking "****ing transfer box, oh well it's going to have to be replaced - lets try this..."

Better than messing around with lights and linkages - what you want to know is whether the diff is actually locking or not.
- Make sure there is a few yards space in front just for safety and on level ground
- Put a bottle jack under O/S end of one axle and raise the wheel just off the ground. Make sure the jack is placed such that if it slips off it will not damage brake lines or other components.
- start the engine
- take handbrake off and hold it on foot brake and change into D
- let the foot brake off very slowly
- what should happen is that the vehicle should stay still but the one wheel will spin round
- hold footbrake on again
- now put it into N and move diff lock lever to left and again put into D
- let the foot brake off very slowly
- what should happen is that the vehicle should try to drive off the jack (you can probably stop it before it happens but no big deal if you've positioned the jack sensibly). This shows the diff is locked
- if the wheel spins again and the vehicle doesn't try to drive off the jack the diff lock is not engaged

cheers
David G

david g said:

Better than messing around with lights and linkages - what you want to know is whether the diff is actually locking or not.
- Make sure there is a few yards space in front just for safety and on level ground
- Put a bottle jack under O/S end of one axle and raise the wheel just off the ground. Make sure the jack is placed such that if it slips off it will not damage brake lines or other components.
- start the engine
- take handbrake off and hold it on foot brake and change into D
- let the foot brake off very slowly
- what should happen is that the vehicle should stay still but the one wheel will spin round
- hold footbrake on again
- now put it into N and move diff lock lever to left and again put into D
- let the foot brake off very slowly
- what should happen is that the vehicle should try to drive off the jack (you can probably stop it before it happens but no big deal if you've positioned the jack sensibly). This shows the diff is locked
- if the wheel spins again and the vehicle doesn't try to drive off the jack the diff lock is not engaged

cheers
David G

Click to expand...

Or infinitely more safe...

Leave the engine off and just try turning the wheel by hand... :doh:

lerk said:

Or infinitely more safe...

Leave the engine off and just try turning the wheel by hand... :doh:

Click to expand...

as was said much earlier in the thread

Ok... Had the V8 in for an MOT which it passed yey

When it was there I borrowed there inspection pit and put the 300tdi over to look at the lock/put a can of WD40 in there!

It was not stuck to start with and went to the left/diff lock. Just didn't light up or engage.

Now it is as slack as I don't know what but still dosn't light up and seems not to engage but yet to test.

I could see the bits moveing and the little twisty knob thing as seen on this video *below* was turning fine so I am guessing it is the sping action bit inside (Dog clutch splines bit) thats stuck and not the selector? Any Ideas???

[ame="http://www.youtube.com/watch?v=TH4r71evEfo"]YouTube- LT230 Difflock Mechanism[/ame]

the daddy said:

Ok... Had the V8 in for an MOT which it passed yey

When it was there I borrowed there inspection pit and put the 300tdi over to look at the lock/put a can of WD40 in there!

It was not stuck to start with and went to the left/diff lock. Just didn't light up or engage.

Now it is as slack as I don't know what but still dosn't light up and seems not to engage but yet to test.

I could see the bits moveing and the little twisty knob thing as seen on this video *below* was turning fine so I am guessing it is the sping action bit inside (Dog clutch splines bit) thats stuck and not the selector? Any Ideas???

YouTube- LT230 Difflock Mechanism

Click to expand...

Get a spanner onto the 'little twisty knob thing' and make sure it's going all the way across, if it is - leave the diff locked and have a bit of a drive around... mine was stuck like this and a 60mph corner sorted it lovely! (would suggest a lower speed though!)

Yer should have done that when it was on the ramp I suppose!

I am thinking a love tap with a rubber mallet may also help... then a bigger hammer till either it frees off or falls off!

i had a similar problem with my 90 the wires to and from the diff lock sensor switch were not there and the terminals missing of the switch and it kept not selecting diff lock and every now and then when it engaged it kept jumping out of diff lock when off roading i just adjusted the linkage and now it works no problem.