Diff lock engaging but not working

Dub Siren · Nov 9, 2023

Hi folks,

The diff lock in both high and low seems to be engaged as it’s lights up on the dash and the gears work!

Works well in high and low on and off road however when taking the Land Rover for short test after a lot of engine work and repairs realised when getting stuck the diff lock wasn’t actually on which made getting unstuck a bit more challenging.

Does anyone know what may be going on here? (Apart from my naiveity and inability to pick a good route off road)

Thanks!!

Brown · Nov 9, 2023

Sometimes the lever mechanism that goes down the side of the gearbox to the front of the centre diff housing develops a lot of slop and fails to transmit sufficient movement . There are little plastic washers, pins and bolts that can all develop wear. If you jack up the Land Rover so that at least one wheel on each axle is free and get underneath (making sure it's all well supported of course!) and move the little tab on the front of the centre diff housing to see if that locks the two axles together. If so, that suggests that the interior mechanism is OK, and there's just too much movement in the linkage. The tab on the centre diff housing uses a spring inside to move a splined slider back and forth to lock the front output shaft to the diff casing, effectively locking the diff. It's on a spring so the slider only moves when the splines are lined up so you don't grind it. However, this means that the slider can stick in one position of the other. For example, sometimes, if there's 'wind up' in the transmission, it can stay in the locked position, because the spring isn't stiff enough to move it. But it can happen in the other direction too, if mechanical wear and accumulated sludge make the slider difficult to move.

Dub Siren · Nov 9, 2023

Thanks a lot! Really appreciate that detail that’s very helpful will get it jacked up asap. Thanks!

miktdish · Nov 9, 2023

When you say you "realised the diff lock wasn't actually on" - how did you know ?
Were the wheels spinning on one side of the car only ?
Or was just one front (or rear) wheel spinning and the other three not turning at all ?

Dub Siren · Nov 9, 2023

miktdish said:
When you say you "realised the diff lock wasn't actually on" - how did you know ?
Were the wheels spinning on one side of the car only ?
Or was just one front (or rear) wheel spinning and the other three not turning at all ?

Ah - all I noticed was that all power was going to the spinning wheels with no traction. And we’re not all locked together - I didn’t notice anything regarding front and back as was mostly focused on getting unstuck. Thanks!

miktdish · Nov 9, 2023

Dub Siren said:
Ah - all I noticed was that all power was going to the spinning wheels with no traction. And we’re not all locked together - I didn’t notice anything regarding front and back as was mostly focused on getting unstuck. Thanks!

I don't think there is anything wrong with your difflock.

With the diff lock on you send drive in equal amounts to both axles. You don't send drive to all the wheels.
It's not a true 4 wheel drive in that sense, more of a part-time 4WD.

Diff lock off, all the drive goes to the easiest (unweighted) wheel to turn.
This could be on the front or rear axle.
Just one wheel will spin.

With the diff lock on, drive is sent to both front and rear axles and will spin one unwieghted wheel on each axle.
Each axle has a differential, in standard format these are not lockable.
One side with 2 wheels in the mud and the other with 2 wheels on the tarmac you will go nowhere.

Different wheel speeds in turns - Harald Pietschmann's 4WD basics

different wheel speeds in turns and the need for differentials

4x4abc.com

Dub Siren said:
Works well in high and low on and off road ...

It isn't advisable to drive on the road (or any grippy surface) with your LT230 diff lock engaged.
Going around a bend all 4 wheels move at different speeds, if the LT230 diff is on, you 'wind up' the gears which can damage the transfer box in dramatic fashion.
BANG, CRUNCH, SHUDDER, STOP - no drive sort of dramatic.

300bhp/ton · Nov 9, 2023

Dub Siren said:
Ah - all I noticed was that all power was going to the spinning wheels with no traction. And we’re not all locked together - I didn’t notice anything regarding front and back as was mostly focused on getting unstuck. Thanks!

Difflock is a centre diff lock, that locks the front and rear props together. You still have open diffs on the axles. This means you can still get cross axled. And allow 2 wheels to spin.

With difflock in the open position you can essentially end up with 1wd off road as it will let 1 wheel spin and not move the other 3.

tottot · Nov 9, 2023

If using your truck in difficult conditions a lot then aftermarket axle lockers, limited slips and torque bias units are available. Choose whichever suits best for you.

Dub Siren · Nov 9, 2023

Thanks a lot! That makes sense, although I find it a bit odd why they wouldn’t all be able to lock as tricky situations is their game. Any idea why they don’t all lock together is it to prevent wear?

Thanks for the heads up I will still hack it up and have a look to see how it all works. Thanks for the explanation I had always thought the diff lock locked all wheels together.

I think I may look into some aftermarket option. Cheers!

tottot · Nov 9, 2023

You are not the only one who has thought that the lock worked on axles as well. The advantage of having drive to both axles at all time is the driving loads are spread between both axles. Good when towing heavy loads on the road. Series landy's doing the same in rear drive only in high would bust a half shaft now and then. I did a few.
If you are once again stuck in similar situation then dabbing the brake with you left foot while keeping some power on with the right [ sort of a human traction control] sends some of the power over to the non spinning wheels and can get you moving again.
Even today few off roader vehicles come with lockers as standard.

miktdish · Nov 9, 2023

@Dub Siren did you buy your Haynes manual yet ?

Smoking Turbo pipe?

Hi Folks, Apologies if questions seem ridiculous I’m rather new to this.. This pipe has a small amount of smoke coming out which I have noticed after it has come off the air filter. Is this smoke bad/ what problem does this indicate? In addition it runs from the small black device which is...

www.landyzone.co.uk

Dub Siren · Nov 9, 2023

miktdish said:
@Dub Siren did you buy your Haynes manual yet ?

Smoking Turbo pipe?

Hi Folks, Apologies if questions seem ridiculous I’m rather new to this.. This pipe has a small amount of smoke coming out which I have noticed after it has come off the air filter. Is this smoke bad/ what problem does this indicate? In addition it runs from the small black device which is...

www.landyzone.co.uk

Yeah I got it as soon as I purchased the Land Rover. That problem is now solved and after a new timing belt it’s running very well!

Dub Siren · Nov 9, 2023

tottot said:
You are not the only one who has thought that the lock worked on axles as well. The advantage of having drive to both axles at all time is the driving loads are spread between both axles. Good when towing heavy loads on the road. Series landy's doing the same in rear drive only in high would break a half shaft now and then. I did a few.
If you are once again stuck in similar situation then dabbing the brake with you left foot while keeping some power on with the right [ sort of a human traction control] sends some of the power over to the non spinning wheels and can get you moving again.
Even today few off roader vehicles come with lockers as standard.

Nice one. Thanks for that - makes a lot of sense. Will certainly try that!

Diff lock engaging but not working

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Different wheel speeds in turns - Harald Pietschmann's 4WD basics

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