Diff Lock Light

[TechnoTurkey]

Hi,

My diff lock light doesnt come on when it should, I have checked the bulb and it looks fine.

What process should I follow to trouble shoot this and how can I tell if the diff lock is actually engaging?

Thanks

[Porny]

Bridge the two wires (that go to the difflock switch) with a short length of wire.... and the difflock bulb should illuminate - thus you can check the bulb and wiring are ok.

Next, to check whether difflock is engaging....

WARNING - THIS IS DONE AT YOUR OWN RISK!!

Jack one of the front wheels up - ideally you need a good trolley jack to do this!! (place in the same direction as the LR)

Put the car in gear (difflock out) - and gently lift the clutch up - covering the foot brake at the same time (hand brake off)

With the difflock disengaged, the the front wheel (that is in the air) should start to turn - but the car itself will not move - as the transmission (in simple terms) is taking the path of least resistance.

If then engage the difflock and do the same test again (i.e covering the foot brake, and slowly let the clutch up) the car should try to move.. as with difflock engaged drive is evenly split between front and wheel axles - and thus will try and drive the back axle too.


Ian

[bigfatsi]

I just sling it in diff lock and drive in a circle. You'll sharp tell as the tyres scrub and it has more resistance.

If it isn't engaging (mine didn't) it could be seized up from lack of use or just need adjusting. Both are quite easy to fix.

But check the bulb first!

Simon.

[SteveG]

I just sling it in diff lock and drive in a circle. You'll sharp tell as the tyres scrub and it has more resistance.

If it isn't engaging (mine didn't) it could be seized up from lack of use or just need adjusting. Both are quite easy to fix.

But check the bulb first!

Simon.

 :?:  :?:  :?:  :?:

we are talking about a centre diff lock here, aren't we?

Steve

[TechnoTurkey]

Yep, centre diff lock......

[bigfatsi]

I just sling it in diff lock and drive in a circle. You'll sharp tell as the tyres scrub and it has more resistance.

If it isn't engaging (mine didn't) it could be seized up from lack of use or just need adjusting. Both are quite easy to fix.

But check the bulb first!

Simon.

 :?:  :?:  :?:  :?:

we are talking about a centre diff lock here, aren't we?

Steve

What's confusing you?

Simon

[SteveG]

What's confusing you?

Simon

If the centre diff lock is in, you still have two open axel diffs, so each wheel on an axle can turn at it's own rate. So how do wheels scrub when centre diff lock is in?

Cheers

Steve

[bigfatsi]

Dunno why but it does! Try it. Discovered that my Audi quattro used to scrub when in diff lock so tried it on my 90 and it worked. Maybe the front wheels go further than the rear due to turning? Haven't a clue! Saves time and risk associated with jacking one wheel up though! Do it somewhere quiet and obviously make sure there's room to turn around  :lol:

Simon.

[AbyssDJ]

What's confusing you?

Simon

If the centre diff lock is in, you still have two open axel diffs, so each wheel on an axle can turn at it's own rate. So how do wheels scrub when centre diff lock is in?

Cheers

Steve

it does it because all four wheels turn at a different rate when you go round a corner... so you essentially end up with a difference in "speed" lets call it between the front and the rear axles.... the front axle takes a wider path, hence why you see four tracks in mud or snow (etc) where a vehicle turns :)

[markyb]

my diff lock light has a mind of its own comes on sometimes flickers and stays on .

so are you talking centre diff not working or just the light

[AbyssDJ]

our light stays on all the time regardless - the switch is stuck. although its off at the moment, because the cable came off when i was underneath it doing something or other! diff lock works fine though

[SteveG]

I understand the principle between turning radii and the rotational difference between the inside wheel and the outside wheel when turning, the point about posting was to check what diff lock this was a test for as in my opinion it's not a guranteed test of a centre diff lock as you have open diffs on each axle.

If I'm right another way of testing diff lock is if you put the vehicle in neutral, jack up a wheel on each axle with the others on wheel chocks  and then turning one of the wheels in the air, the other wheel in the air will move at the same rate.

Cheers

Steve

[bigfatsi]

my diff lock light has a mind of its own comes on sometimes flickers and stays on .

so are you talking centre diff not working or just the light

There are numerous things that can go wrong on your diff lock. Either the lock engages or not or the light says it's engaged or not when it is or it's not! Glad I made that clear  :lol:  :lol:

First thing to do is to see if diff lock is engaging. As mentioned above there are a few ways to do it ranging from driving in a tight circle to removing a prop shaft. Up to you how you find out. If it's engaging and the light isn't on the most obvious cause is the bulb has gone but it could be the switch on the box. If it's not engaging but the light says it is, it could be the switch or perhaps a short somewhere.

HTH

Simon.

[TechnoTurkey]

Thanks for all the answers everyone!  I'll have a proper look at the weekend.