Hi, I am new 4x4 off roading but I have to say so far it has been fun. But i am unsure if my diff lock works properly can anyone help. I got beeched on a mud run and had to towed out - diff lock was locked in and light was on but rear wheels were spinning but the fronts were doing nothing. Got home jacked up back end attempted to drive wheels span engaged diff lock and it wanted to come off the jack. I then had a look at diff lock mechanism and it all seeems free. But today whilst playing went to go up a slope- loose dirt etc and under power the back wheels just spun again diff lock light was on and lever right over to left in low range. I rev back down, got under veh and checked that the lever was throwing the diff lock over which it appeared to do. anyone got any ideas ? Thanks. its a H plate disco v8 inj if it makes any difference.
Sounds like it is touch and go when it comes to engaging Diff Lock.
If it works, you should be able to jack the back axle so the wheels are off the ground, and it should drive away. It is clear from what you have explained that the diff lock has worked, but seems not to have engaged when you got stuck.
Try making sure nothing is stopping the little linkages from going fully over.
Also, if there is too much slop in the linkages that too might reduce engagement.
Charles.
If it works, you should be able to jack the back axle so the wheels are off the ground, and it should drive away. It is clear from what you have explained that the diff lock has worked, but seems not to have engaged when you got stuck.
Try making sure nothing is stopping the little linkages from going fully over.
Also, if there is too much slop in the linkages that too might reduce engagement.
Charles.
Widget
New Member
If both rear wheels were spinning it would mean that the fronts had more traction than the rears - which just doesn't stack up. Its usual for one or both of the front wheels to spin, not the rears on an upslope - regardless of whether the diff locked or unlocked.
The only way I can see that the rears could spin is if you have the diff locked and apply enough power break the grip they have.
Were both front wheels definitely stationary with the rears spinning, or was the front nearside having a crafty spin on its own? It's not unusual because the weight of the driver gives the front offside marginally more traction.
Now - there is another possibility. If a previous owner has busted a CV or front halfshaft they might have locked the diff fork and disconnected the linkage pin. This would explain the symptoms - as you describe them.
Which leaves a question - did you drive it off the jacks with the rear wheels in the air?
Let us know what the outcome is - if you don't coem back and tell us we'll assume its cos yer a crap driver.
If both rear wheels were spinning it would mean that the fronts had more traction than the rears - which just doesn't stack up. Its usual for one or both of the front wheels to spin, not the rears on an upslope - regardless of whether the diff locked or unlocked.
If both rear wheels were spinning, and the front wheels were stopped, then FOR SURE the diff lock was NOT engaged. END.
NO further discussion.
The only way I can see that the rears could spin is if you have the diff locked and apply enough power break the grip they have.
WRONG! If the centre diff is locked and one or both rear wheels are spinning, then one or both FRONT wheels MUST also be spinning. END.
Were both front wheels definitely stationary with the rears spinning, or was the front nearside having a crafty spin on its own? It's not unusual because the weight of the driver gives the front offside marginally more traction.
Believe the man ....
Now - there is another possibility. If a previous owner has busted a CV or front halfshaft they might have locked the diff fork and disconnected the linkage pin. This would explain the symptoms - as you describe them.
NO! If this was the case it would be permanently centre diff locked.
His problem is he can not get the diff locked at all.
Which leaves a question - did you drive it off the jacks with the rear wheels in the air?
If he did, the DIFF MUST HAVE BEEN LOCKED.
Let us know what the outcome is - if you don't coem back and tell us we'll assume its cos yer a crap driver.
But at least he is trying to get a basic understanding of differentials and the effects thereof, whereas some other people just think they know.
CharlesY
Widget
New Member
Well I beg to differ and choose to discuss it. If the diff is unlocked - surely either of the front wheels would spin first? Not the rears. If the diff is locked then a front wheel would have to be spinning too. Either way it doesn't make sense for the rears to be spinning without the fronts losing traction too.
I know - did you read what followed properly and understand it?
Well perhaps you should try. The diff, props and transfer box are on the offside too, which is why offside springs have a higher rate than nearside on Disco1, RR, Ninetys, One Tens, 127, 130's and Defenders. On Ninetys and early Defenders the fuel tank is on that side too, making it more common.
err...YES! Ever driven a land rover with a prop removed? You lock the centre diff. The symptoms described are that he's physically locking the diff (arm is engaging and the light is coming on) and and seemingly just getting rear wheel drive - having incomplete drive to the front wheels would explain the symptoms. The diff lock light is designed to come on when its engaged, not just when you push the lever across.
Agreed - but if he jacked up the front and drove it off with the rears then it didn't demonstrate that any drive was going to the front, only to the rear.
Either the symptoms are being described incorrectly, or there's something wrong with the car. The subtley you've clearly missed in an attempt to look vastly knowledgeable and superior is the difference between locking the diff and getting drive to both axles. Shame on you for responding in such a nasty, humourless and aggressive manner.
Ka0s
New Member
i think charlsey gets a bit enthusiastic with his posting, i dont think he meant to sound nasty matey
Posts like this are good, everyone gets to learn a bit and find out if what they think they know is correct, hence my lack of input on this thread
I agree with joo tho widget, the issue here isnt the lock engaging, its the lack of drive to the fronts when its engaged
Posts like this are good, everyone gets to learn a bit and find out if what they think they know is correct, hence my lack of input on this thread
I agree with joo tho widget, the issue here isnt the lock engaging, its the lack of drive to the fronts when its engaged
Either the symptoms are being described incorrectly, or there's something wrong with the car. The subtley you've clearly missed in an attempt to look vastly knowledgeable and superior is the difference between locking the diff and getting drive to both axles. Shame on you for responding in such a nasty, humourless and aggressive manner.
Nope. Life is too short. I was just helpful, analytical, and correct.
Your post shows you do not and apprently WILL NOT understand differentials yet, so that's it as far as I am concerned. No more to say that hasn't been clearly said, and Listers must choose who to believe.
Time will tell as it always does.
so NAAAH NAAH NA NA NAAAH to you,
CharlesY
Nope. Life is too short. I was just helpful, analytical, and correct.
Your post shows you do not and apprently WILL NOT understand differentials yet, so that's it as far as I am concerned. No more to say that hasn't been clearly said, and Listers must choose who to believe.
Time will tell as it always does.
so NAAAH NAAH NA NA NAAAH to you,
CharlesY
Pikey
Dummy Ejection Facilitator..
I have spun my wheels in low 2nd and diff lock engaged. Whilst attempting a very steep and loose railway embankment. So steep when we climbed up it for a look at it. It was too steep to walk back down.
So it is possible to spin your wheels with difflock engaged. However as said earlier all 4 wheels were spinning on mine.
So it is possible to spin your wheels with difflock engaged. However as said earlier all 4 wheels were spinning on mine.
TheMunster
Active Member
Diff's are rather simple in operation. Like Charlsey says, if one axel is moving and the other isnt then the Diff isnt locked, no matter what everything else is telling you.
Thats what the diff does, its a central diff, it dosent lock wheels independant of the axel they are on (a lot of people seem to think this for some reason).
This does mean you only need to loose traction on one tyre on each axel THEN you will spin if your diff is locked. OP : You 100% sure one of your front wheels wasnt spinning as well? Only one of them needs to be moving fo you to get stuck.
Thats what the diff does, its a central diff, it dosent lock wheels independant of the axel they are on (a lot of people seem to think this for some reason).
This does mean you only need to loose traction on one tyre on each axel THEN you will spin if your diff is locked. OP : You 100% sure one of your front wheels wasnt spinning as well? Only one of them needs to be moving fo you to get stuck.
battenberg
Well-Known Member
An essential understanding of differential's is a pre-requisite of driving a 4x4 if you are going to be messing about with your diff lock.
there is a good animation here: Howstuffworks "Open Differentials" which shows how they work.
But dont be confused... the disco (along with most 4x4's) has three diffs. One in each axle and one in the center joining the two axles.
The diff lock works only on the center diff and quite literally 'provides equal amounts of rotation simutaniosly' to both the front and the back axle differentials once engaged.
The center diff lock only locks the center diff. NOT the diff in the axle (unless you got a tricked up disco with air lockers or soleniod locks etc...) It is important to understand this and the effect it has on your traction. Only then should you be engaging your centre diff.
Your post could also be mis-leading as you suggest:
"rear wheels were spinning but the fronts were doing nothing"
there is a big difference between a rear 'wheel' spinning and rear 'wheels' spinning when talking about trouble shooting a locking diff - by this do you suggest that you have lockers on the axles as well?
there is a good animation here: Howstuffworks "Open Differentials" which shows how they work.
But dont be confused... the disco (along with most 4x4's) has three diffs. One in each axle and one in the center joining the two axles.
The diff lock works only on the center diff and quite literally 'provides equal amounts of rotation simutaniosly' to both the front and the back axle differentials once engaged.
The center diff lock only locks the center diff. NOT the diff in the axle (unless you got a tricked up disco with air lockers or soleniod locks etc...) It is important to understand this and the effect it has on your traction. Only then should you be engaging your centre diff.
Your post could also be mis-leading as you suggest:
"rear wheels were spinning but the fronts were doing nothing"
there is a big difference between a rear 'wheel' spinning and rear 'wheels' spinning when talking about trouble shooting a locking diff - by this do you suggest that you have lockers on the axles as well?
Thank you all for your input,
The story so far - tonight i have been checking operation off diff lock mechanism. CharlesY - suggested free play in mechanism and something stoping operation. On checking the link rod from bottom of main lever to actuation lever on top of diff it was "very loose" had a lot of up and down movement and appears to have play side to side. If the condtions were right - where the pin comes down in to the main lever arm - the end of the pin would catch a bolt head on top of diff assembly preventing it from pushing all the away across. Also if I moved lever from under truck with the aid of screw driver as lever it will throw further so there may be play in pivot at the top which i will get off tomarrow. So it may just be a worn bit of linkage.
Points that were raised-
When i checked by jacking up rear end to see if diff lock worked I only jacked one rear wheel as I thought all power would go to wheel with least resistance. With diff lock engaged it did want to drive off jack but I didnt actually drive it off the jack..
When the rear wheels lost grip with diff lock in I am almost sure that both rears were spinning and not the front as there were too dips when rear wheels had begun to dig in and no evidence in ground that the nearside frt had been spinning - but having read your replies i am not 100% sure.
There arent any individual diff locks on it as far as I know - if there are the bloke i bought it off didnt tell me which button to press!!
Or you may be right I mayjust be not very good at this off road stuff YET
Thanks Again for your help and I will let you know waht else I find.
The story so far - tonight i have been checking operation off diff lock mechanism. CharlesY - suggested free play in mechanism and something stoping operation. On checking the link rod from bottom of main lever to actuation lever on top of diff it was "very loose" had a lot of up and down movement and appears to have play side to side. If the condtions were right - where the pin comes down in to the main lever arm - the end of the pin would catch a bolt head on top of diff assembly preventing it from pushing all the away across. Also if I moved lever from under truck with the aid of screw driver as lever it will throw further so there may be play in pivot at the top which i will get off tomarrow. So it may just be a worn bit of linkage.
Points that were raised-
When i checked by jacking up rear end to see if diff lock worked I only jacked one rear wheel as I thought all power would go to wheel with least resistance. With diff lock engaged it did want to drive off jack but I didnt actually drive it off the jack..
When the rear wheels lost grip with diff lock in I am almost sure that both rears were spinning and not the front as there were too dips when rear wheels had begun to dig in and no evidence in ground that the nearside frt had been spinning - but having read your replies i am not 100% sure.
There arent any individual diff locks on it as far as I know - if there are the bloke i bought it off didnt tell me which button to press!!
Or you may be right I mayjust be not very good at this off road stuff YET
Thanks Again for your help and I will let you know waht else I find.
mmaddock
New Member
I have to say, I ready you post as extremely rude and aggressive.
Having been out laning (can I call it laning JB? was more like a mountain pass to me!) with Jonathan, I'm pretty sure he understands what he's talking about! - respect to you JB for not boasting about your 'superior' knowledge and leaving 'Mr Correct' to it! People who blindly think they are correct with no discussion to the contrary I usually find are not, but it is best to leave them to think they are right!
I think you were right about this forum.
Matt
Ka0s
New Member
People who also clearly do not read the whole post before jumping in are usually best to be left blindly posting........
The to and fro that has resulted from this post has probably cleared things up for a few people. I thought we had moved on from questioning the attitude of people posting?
Take5
New Member
Just to add my experience from dicky diff locks. My old V8 Auto Defender had a dicky diff lock. Engage it and it worked fine. Go trialling and leave it in low box diffs locked, by the second or third section it was clearly not working and have photographic evidence of this (my old avatar for example had both fronts stationary with one rear spinning). Disengage difflock, reverse up, re-engage and it worked as it was supposed to.
Don't actually know what happened to it as I sold it before getting the transfer box sorted out.
Don't actually know what happened to it as I sold it before getting the transfer box sorted out.
mmaddock
New Member
Mine does the same thing, just got to check the light is on before hitting any tricky hills etc.! One nice thing about the 38A was that you didn't have to think about engaging / disengaging it!
Matt
Widget
New Member
Thanks for your kind words Matt. There are those who pontificate, and those who do. I prefer to read the words of the latter and learn from those who demonstrate a generous spirit. Without overstating the case, I've been laning for 20 years and have learnt a great deal from some good people. A particularly generous fella was Tim Webster who used to write for LRO in the early 90's and opened up many of the lanes we now enjoy on Wales, he was such a person and I learnt a great deal from him and similar folk.
Today I've been out in the Lake District. Drove up the rock steps on Parkamoor - it seemed a bit trickier than the last time. At the top I realised I'd forgotten to lock the centre diff.
I always used to lock the centre diff as soon as I reached a lane as a matter of habit, until recently when some 'pundit' suggested I didn't need to until it got really loose. Well having had a couple of episodes recently where I've forgotten to slide the little lever across, I'm going back to my old ways. I'm far more likely to bust a half shaft by not having it locked than by having it locked and accepting a small amount of wind-up.
On another similar point, I also tend to walk away from those who boast 'I did that lane - and I didn't even have the centre diff locked', for they know not what they do.
I prefer to read the words of the latter and learn from those who demonstrate a generous spirit. Without overstating the case, I've been laning for 20 years and have learnt a great deal from some good people. A particularly generous fella was Tim Webster who used to write for LRO in the early 90's and opened up many of the lanes we now enjoy on Wales, he was such a person and I learnt a great deal from him and similar folk. Today I've been out in the Lake District. Drove up the rock steps on Parkamoor - it seemed a bit trickier than the last time. At the top I realised I'd forgotten to lock the centre diff.
I always used to lock the centre diff as soon as I reached a lane as a matter of habit, until recently when some 'pundit' suggested I didn't need to until it got really loose. Well having had a couple of episodes recently where I've forgotten to slide the little lever across, I'm going back to my old ways. I'm far more likely to bust a half shaft by not having it locked than by having it locked and accepting a small amount of wind-up.
On another similar point, I also tend to walk away from those who boast 'I did that lane - and I didn't even have the centre diff locked', for they know not what they do.
Attachments
Jason2
Well-Known Member
The first time I went off road with mi 2 sprogs we were following a road book at an organised event with some experienced off roaders.From green laning we ended up in a quarry so I just followed like you do,forgetting in the excitement to put "diff lock" on shot up a massive banking only to get half way up,knowing immediately my mistake when the front wheels started spinning, dived on brakes,slid back down,went side ways & nearly rolled & had to be winched out.
You learn by your mistakes I kin did anyway
I find the best way to explain yeh "Diff lock" is if you drive yeh front wheels of a cliff (Dont try it ) then put it in reverse they will just spin, put your "diff lock" on and your rear wheels will drive you back on to the cliff even though your front uns are still spinning!
dived on brakes,slid back down,went side ways & nearly rolled & had to be winched out.You learn by your mistakes
I kin did anyway I find the best way to explain yeh "Diff lock" is if you drive yeh front wheels of a cliff (Dont try it
) then put it in reverse they will just spin, put your "diff lock" on and your rear wheels will drive you back on to the cliff even though your front uns are still spinning!Just to let you all know,
I replaced the link rod from the main lever to actuator - i got all the little pins etc with it from a land rover dealer, when fitted there was little or no slop in linkage giving a postive action and then when engaged a reassuring metalic knock could be heard all the time, less side ways movement on selcting lever.
Went out on sunday no problems at all
Thanks again
I replaced the link rod from the main lever to actuator - i got all the little pins etc with it from a land rover dealer, when fitted there was little or no slop in linkage giving a postive action and then when engaged a reassuring metalic knock could be heard all the time, less side ways movement on selcting lever.
Went out on sunday no problems at all
Thanks again
