Diff Lock does not unlock

I am pretty sure the other side [ if you mean the other wheels shaft ] will be fine.[ It would be very unusual for both half shafts to go at the same time. ] That over load on the shaft will be due to the displacement on the ball housing after it came loose, check for damage on the housing's inner flange area. Pull the broken shaft from the diff and check the inner end splines are straight and not damaged. If ok then should be fine to just drain and refill diff. When you have diff plug out put a finger in and feel for any bits

And did you find anything of the shaft support bearing ? It would have been at the end of the main axle case but could have been chewed up and spat out of the gap between the axle and the housing when it became loose.

tottot said:

I am pretty sure the other side [ if you mean the other wheels shaft ] will be fine.[ It would be very unusual for both half shafts to go at the same time. ] That over load on the shaft will be due to the displacement on the ball housing after it came loose, check for damage on the housing's inner flange area. Pull the broken shaft from the diff and check the inner end splines are straight and not damaged. If ok then should be fine to just drain and refill diff. When you have diff plug out put a finger in and feel for any bits

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+1

looks like she has been a bit warm in there, just done both my swivels and neither look like that with 200k miles on them

Have a good wipe out and look for debris..

the box spanner worked ok then..?

tottot said:

And did you find anything of the shaft support bearing ? It would have been at the end of the main axle case but could have been chewed up and spat out of the gap between the axle and the housing when it became loose.

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Hi @tottot I found a few splits of metal some about 10mm, pretty neat and sharp, like machined, but not much. I caught the ones I could with a long flat screwdriver, used a flashlight within the axle, looked clean, but you can never be so certain.

All those nasty bits could have well luckily fell off, indeed, when all hell was loose.

Splines are in perfect shape, should have taken a picture, but this is good news.

@Cavey_P38 The socket worked great indeed. Wasn't that tight at all.

So I checked the right hand side, and it seemed fined, but I'm very puzzled that I can rotate the shaft by hand with a gear engaged, it doesn't make sense.
Bearings within the CV joints appeared ok, not fabulous, both CV joints had leakage so will replace all seals and grease.

Some sealant was heavily applied behind on the drive flange and on its 5 bolts (black and thick), would you know what product is this? I this standard?

Digging the web now for the best deals on CV seals + grease kits and a new LH shaft.

You can rotate the shaft by hand even if the prop shaft can not turn because the diff is doing it's job as it should. If the axle was complete and jacked up wheels off the ground, when you turn one wheel forward the other side will turn in reverse. It is what a diff does, allows wheels to turn at different speeds so vehicle can go around corners.
Flange and ball housing have paper gaskets, some like extra sealer but I smear them with grease when fitting.

could be a

MechanIX said:

Hi @tottot I found a few splits of metal some about 10mm, pretty neat and sharp, like machined, but not much. I caught the ones I could with a long flat screwdriver, used a flashlight within the axle, looked clean, but you can never be so certain.

All those nasty bits could have well luckily fell off, indeed, when all hell was loose.

Splines are in perfect shape, should have taken a picture, but this is good news.

@Cavey_P38 The socket worked great indeed. Wasn't that tight at all.

So I checked the right hand side, and it seemed fined, but I'm very puzzled that I can rotate the shaft by hand with a gear engaged, it doesn't make sense.
Bearings within the CV joints appeared ok, not fabulous, both CV joints had leakage so will replace all seals and grease.

Some sealant was heavily applied behind on the drive flange and on its 5 bolts (black and thick), would you know what product is this? I this standard?

Digging the web now for the best deals on CV seals + grease kits and a new LH shaft.

Click to expand...

Could be a swivel seal kit will be your best option, mine came with all gaskets and swivel hub seals and a sachet of one shot grease to refill the swivel

just paid about 18.50 + VAT for mine, they are not handed and u can do just one side, but i would be tempted to do both while you at it.

then just have to find a shaft, not sure if there are different no of splines for different ages or 90 to 110

but sure someone will know, really must get a parts book..

good luck. not too hard just undoing the swivel bolts next to axle tube takes time and effort and prob a good spanner, hammer to shock it and a 14mm rachet spanner once it is free a bit

the utube vid is a good guide especially the dutch one.

Greetings gentlemen,
I've been digging internet for parts over the weekend, can't believe the price difference for the shaft between Britpart, GKN (which was what I got) or genuine.
Rougly Britpart: 30€, GKN 115€, Terrafirma about 200€, Genuine over 365€... I see that I can get a brand new GKN CV joint + shaft for 278€.

What would you go for?

I would go for GKN tbh, they are an OEM company and of a high standard. I have used GKN bearing etc before and they hold up well.
I would have no worries using GKN, but I would worry about the cheap britpart - who knows what chinesium it’s made from.

I don’t have pockets deep enough for genuine so always go OEM where possible

MechanIX said:

<snip>
So I checked the right hand side, and it seemed fined, but I'm very puzzled that I can rotate the shaft by hand with a gear engaged, it doesn't make sense..

Click to expand...

If you lift both wheels off the ground (unweighted) you can turn either wheel without rotating the diff input/drive flange. If you turn the offside wheel clockwise the nearside will turn anti clockwise.
If you put one wheel on the ground (weighted) or stop it turning, then when rotating the unwieghetd wheel the drive flange will rotate.

In essence the force is transfered to the easiest to rotate object. If the car is 'in gear' and both wheels are unweighted turning one wheel will transfer the force to the easiest path and rotate the other wheel. if you put the car in neutral the other wheel will still rotate as the gear ratio is 1:1 whereas the drive flange is 3.54:1 (ie you turn the wheel once and the drive flange turns 3.54 times and so takes more force to move it). If you weight the other wheel you could turn the wheel, with the car in neutral, but you also will spin a whole load of drive chain components it won't be 'easy'.

So: In gear with the transfer box in 2WD and the engine running the force will transfer along the easiest path. If you unweight any 1 wheel, it will turn and all the others will stay still.If you unweight 2 wheels on the same axle then (if everything is perfect) both wheels will turn in opposite directions.
If you lock the center diff (ie put the car in 4WD) then force will be transfered to both the front and rear axles. If 1 wheel on each axle was unweighted then these unweighted wheels would rotate and the car would not move.
Is the Defender a 4WD car = No
In 2WD its a single axle, 1 wheel drive car and in 4WD its a twin axle, 2 wheel drive car.

In 2WD with one wheel unweighted (off the ground) or with a broken half shaft, in gear, the engine will spin the drive shaft with the least resistance and you will not move.
In 4WD the center diff (or transfer box) will transfer half of the force to the rear axle and if both of those wheels are weighted it will propel the car forward.

Hope that makes sense.

Thanks @flat , I'll go for GKN again then. Checked the price direct through LR: 366€ the shaft + 326€ the pivot. Crazy! Ordering now with CV joint servicing kits and new bearings for both sides, l'll try to do this right. Got a pull meter on Amazon also so I can fine tune the CV joint preload.

You are wrong miktdish, with all wheels on the ground the Defender is four wheel drive all of the time, all wheels are being driven which is the case most of the time. As you note traction/drive is lost when a wheel leaves the ground. It is never two wheel drive like a series can be. I see where you are coming from but the use of the term " two wheel drive" is misleading as is one wheel drive with regards to a single axle car after all as you point out when a wheel is unweighted there is no drive at all.

tottot said:

You are wrong miktdish, with all wheels on the ground the Defender is four wheel drive all of the time, all wheels are being driven which is the case most of the time. As you note traction/drive is lost when a wheel leaves the ground. It is never two wheel drive like a series can be. I see where you are coming from but the use of the term " two wheel drive" is misleading as is one wheel drive with regards to a single axle car after all as you point out when a wheel is unweighted there is no drive at all.

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Perhaps it's just an understanding thing. IMO to be 4WD all wheels should be driven whether on not they are weighted. I do agree though that the lockable central differential does drive both front and rear prop shafts all the time and if all 4 wheels are similarly weighetd then all 4 wheels are 'driven' so it is classed as a 4WD (which I find misleading).
Yes, series landrovers had a yellow lever that disegaged the front prop shaft so they were a 2 wheel, (rear axle only) or 4 wheel (both axles) drive system which was superceeded by the LT230.

Limited Slip Differentials are the answer (or some form of viscous coupling) ...... one day i'll fit one to my front axle

You are correct in thinking many people think a four wheel drive, drives all wheels all of the time. Once came across a [ early ] rangy driver cursing the hell out of his car in John Cleese style, stuck in a ditch with two wheels spinning in the mud and the ones on the road not turning. He just thought it was broken. A couple of left foot dabs on the brake with a bit of power on sent some drive over to the wheels on the road and out it came. He did not understand and still thought it was broken.
The only " full" four wheel drive system is as fitted to my Massy Ferguson tractor with diff locks available on both axles. Forget to switch them out and it will not want to turn unless on very slippery ground.

Excellent discussion, learnt a lot from you. Also read this afterwards which reinforces your statements:
outsideonline.com/2096381/4wd-vs-awd-whats-difference

The braking trick is also detailed and explain how it redistributes traction over all wheels. It all makes sense now!

Hi Everybody. I hope you're all doing great and so are your Landies!

Got the parts (at last!), Brexit + Covid, took 3 bloody weeks.

Took the opportunity to change all seals, greased bearings properly on left CV joint as it was in such a mess. Didn't take pictures though... But looks pretty neat now

Went into Unlock at first shot. Drove about 200m,
Went into Lock, kept on a straight line, switched back to Unlock,
Went into Lock again (played a bit between High and Low worked fine although shaking hard), took a 90° corner,
Couldn't Unlock... Then kept trying, went around my block basically... Couldn't Unlock at all.

Parked, Lifted the right wheel, which I saw unwinding for the first time
Went into Lock again. Keeping it that way!!!

The diff felt pretty cranky went I was trying to Unlock, was shaking the chassis pretty hard between neutral and Unlock, it's all I could do and shifting between High and Low.

Didn't feel exactly like usual I think.

Is it normal that just going around the block builds such a windup and prevents me from Unlocking?

MechanIX said:

Hi Everybody. I hope you're all doing great and so are your Landies!

Got the parts (at last!), Brexit + Covid, took 3 bloody weeks.

Took the opportunity to change all seals, greased bearings properly on left CV joint as it was in such a mess. Didn't take pictures though... But looks pretty neat now

Went into Unlock at first shot. Drove about 200m,
Went into Lock, kept on a straight line, switched back to Unlock,
Went into Lock again (played a bit between High and Low worked fine although shaking hard), took a 90° corner,
Couldn't Unlock... Then kept trying, went around my block basically... Couldn't Unlock at all.

Parked, Lifted the right wheel, which I saw unwinding for the first time
Went into Lock again. Keeping it that way!!!

The diff felt pretty cranky went I was trying to Unlock, was shaking the chassis pretty hard between neutral and Unlock, it's all I could do and shifting between High and Low.

Didn't feel exactly like usual I think.

Is it normal that just going around the block builds such a windup and prevents me from Unlocking?

Click to expand...

yes because you are on a hard and high friction surface so there is no way the wheels can slip to allow steering etc, hence why it was all juddery and weird.
You are lucky you didn’t wind it up and break something tbh.
Got access to a field?

flat said:

yes because you are on a hard and high friction surface so there is no way the wheels can slip to allow steering etc, hence why it was all juddery and weird.
You are lucky you didn’t wind it up and break something tbh.
Got access to a field?

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What he said

get it in a soft environment where you would use diff lock or you will break something.

Diff lock is for when you are about to enter some serious ground conditions not a road. even a more modern vehicle will struggle to come out of diff lock on a hard surface (L200 )

have to reverse and mess about to get it out, if i forget and leave it in when i transit from field to track

I reckon since i have had the insa turbos i have used mine once or twice round the farm in probably 6 years , and we are in bog land here..

Unless your Pay and Play or doing some very serious off roading you will rarely use it, handy to know it is there and works but test it in the appropriate environment.

flat said:

yes because you are on a hard and high friction surface so there is no way the wheels can slip to allow steering etc, hence why it was all juddery and weird.
You are lucky you didn’t wind it up and break something tbh.
Got access to a field?

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I had to try... Was stupid I admit... No straight access to a field here I'm afraid, but if tomorrow's weather is nice, I'll reach the mountains where there are some proper tracks, the land is pretty dry those days though...

Now I understand the mechanics of it at least... At a cost!!! And why reversing back till the position where you engaged Lock could catch all the plays back and allow you to Unlock.

We drove quite a fair bit with Lock engaged on tarmac before all hell broke loose (~8km... ).

Thank you for all your explanations and all. This is quite a machine, gotta take care of it.

Will do right CV joint soon, there is a small leak, and brake pads and new discs, it's not in a good state at all...

Thank you guys, you rock!

MechanIX said:

I had to try... Was stupid I admit... No straight access to a field here I'm afraid, but if tomorrow's weather is nice, I'll reach the mountains where there are some proper tracks, the land is pretty dry those days though...

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a gravel car park or a grass field will work as will allow wheel slip.

tbh you rarely need difflock with normal use