 | Home > Technical > diff lock? |
 
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6318   
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Ignoring the light, how would you know if you're stuck in diff lock?
And should the lever left to right be very easy / light unlike moving high / low? |
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13th Dec 2014 7:59am |
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| bpman Member Since: 21 May 2008 Location: Oslo Posts: 8069 
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Your tyres wil scrub on Tarmac when turning , steering will feel odd
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13th Dec 2014 9:05am |
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| Cupboard Member Since: 21 Mar 2014 Location: Suffolk Posts: 2971  
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The lever is smoother putting in the diff lock compared to changing range, but it shouldn't be loose.
On the three I've driven there's been a soft detent in either position, but both positions have a bit of play. I don't know if it's correct or not, but I find that it will sometimes go straight in and the light comes on, other times I have to hold the lever all the way across and drive for a little bit. |
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13th Dec 2014 9:33am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6318
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Bpman ......
So scrubbing on inside and outside of both front tyres.....feeling of understeer as if the tryres are over inflated which they aren't? |
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13th Dec 2014 10:07am |
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| davew Member Since: 02 Jan 2012 Location: North Yorkshire Posts: 888 
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The simplest way to check it is to jack up one wheel with a trolley jack and then see if you can gently drive the vehicle forward. If you can, difflock is in, if you can't and the jacked up wheel just spins and you go nowhere then difflock is out.
If you've engaged the difflock and then released it, sometimes wind up in the transmission can keep the difflock locked in. Jacking up the wheel will release that tension and you may well hear it drop out with a clunk when you start to drive. http://www.yorkshireoffroadclub.net/ |
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13th Dec 2014 10:31am |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558
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don't think its a good idea to jack one wheel up and try and drive it even gently
if the diff lock is locked when you drive sharp turn slowly , the whole defender would feel springy (as you tried to move it would be like you are connected to a large bungee ) if that makes any sense the other thing is does the light work , if you lock the diff does it light up the diff lock switch is on the diff not the lever if you move the lever the light will not always come on unless the diff locks sometimes you have to move few feet for the diff to lock and put light on same as moving lever to unlock (if you got bit of transmission wind up ) the light will stay on ,until you move few feet to un wind transmission then the diff will unlock and light will go out |
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13th Dec 2014 11:48am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6318
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Forgive my ignorance please.
There have been a few times where I pulled off my drive which is a right turn onto the road and like a bungee however I thought it was like I was zooming off and then the accelerator had died? When you mentioned that if I lift one wheel it should rotate if not in diff lock presumably this is only when the gbox is in neutral? |
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14th Dec 2014 8:50am |
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| couplands Member Since: 31 Aug 2011 Location: Peak District & Cornwall Posts: 1826 
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^^^yes, should have said put it in neutral and hand brake off. But chock some of the wheels on the ground, just for safety's sake...
Cheers Simon |
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14th Dec 2014 9:27am |
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| diesel_jim Member Since: 13 Oct 2008 Location: hiding Posts: 6133 
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^^^^ Or just jack up one front wheel, with the main box in neutral and (if) the difflock disengaged you should be able to rotate the airborne wheel by hand.
If the difflock is engaged then you won't be able to turn it. Doesn't matter about the handbrake because (with the difflock disengaged) it only locks onto the rear propshaft, so the front axle will be able to rotate everything right up to the centre diff. |
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14th Dec 2014 10:05am |
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| davew Member Since: 02 Jan 2012 Location: North Yorkshire Posts: 888
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OK, as too many people are misinterpreting what I said, heading off into all sorts of weird and convoluted variations, I'll expand on it.
Without diff lock in if any wheel breaks traction all the drive will go to that wheel. With diff lock in the centre diff ensures that the drive is sent to both axles regardless of traction. As a result, jacking a wheel up in the air ensures that wheel has lost traction so if the diff lock is out then all the available drive will go to that wheel, preventing the vehicle from moving. If the diff lock is in, the drive will also go to the axle without a wheel lifted and because both wheels are on the ground and have traction on that axle, the vehicle will be able to move. 1) Jack a wheel up while on level ground - I prefer the front right as it's easiest to see out of the drivers window on a RHD vehicle. 2) Get in the vehicle and with the transmission brake off, transfer box in high and at tick over put the gearbox into 1st gear and slowly let out the clutch to creep forward. (On an auto, put it in drive and slowly let your foot off the brake). 3) If at this point the front right wheel spins freely and the vehicle does not think about moving anywhere then diff lock is not engaged. If, on the other hand the wheel does not spin and the vehicle feels as if it's starting to drive forwards or stalls, the diff lock IS engaged. 4) If the wheel does spin so the diff lock is out, make sure the wheel is not spinning (use the brakes and dip the clutch) and engage diff lock. Try step 2 again and confirm that the diff lock is engaged. There is nothing vague about this method and it is 100% certain if the diff lock is in or out, none of the "feeling springy" stuff that leaves it up to individual interpretation or relies on wearing a couple of thousand miles of life off your tires. It takes a couple of minutes at most and you have a certain answer each way. You are not actually expecting to drive off the jack (although if you do it's unlikely to be a problem), all you are doing is seeing if you can drive forward if you wanted to. If you really can't grasp the concept I'll make a video of it. The only thing I would say is don't get too carried away if diff lock is not engaged. Prolonged running with 1 wheel in the air and the diff lock not engaged can damage the centre diff. Don't let the front wheel spin at 200MPH, you don't need any engine revs other than just normal idle RPM. I know someone who decided this was a good way to dynamically balance his wheels, he save a tenner on getting the wheels balanced but cost himself £120 and a day replacing the transfer box after spinning the front axle wheels at 70MPH for 20 mins. http://www.yorkshireoffroadclub.net/ Last edited by davew on 14th Dec 2014 12:47pm. Edited 1 time in total |
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14th Dec 2014 11:48am |
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| couplands Member Since: 31 Aug 2011 Location: Peak District & Cornwall Posts: 1826
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^^^ whats wrong with just jacking a wheel up and turning it (by hand) to see if the diff lock is engaged or not..?
Or does that not work..? cheers simon |
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14th Dec 2014 12:45pm |
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| davew Member Since: 02 Jan 2012 Location: North Yorkshire Posts: 888
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It does work, it's the test I use if the engine is dead, it's just quicker and easier to jump in the vehicle and run a full test from the cab if the engine is OK. I also feel it gives a better test for a damaged centre diff as I've had them in the past where, due to damage to the diff, they only lock up in specific places of their rotation which might go unnoticed using the "manual" method. It can also free off a locked diff that is stubborn to release through the normal methods as just jacking the wheel up to release the wind up doesn't always allow the diff lock to pop out. http://www.yorkshireoffroadclub.net/ |
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14th Dec 2014 1:10pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6318
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So diff lock is ok. Thank you.
I presume it's also normal for the lever to keep moving over to the left / mid position while driving ie every few hundred yards the lever can be pushed about an inch back to the right where I would have assumed it should stay? |
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14th Dec 2014 2:23pm |
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| ericvv Member Since: 02 Jun 2011 Location: Near the Jet d'Eau Posts: 5816 
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^^ Caterham, perfectly normal.
 I had that verified by my dealer long time ago I must admit, but when the diff lock is in the off (right) position, the lever can indeed move an inch to the center without the diff actually coming on (light should stay out).
Eric You never actually own a Defender. You merely look after it for the next generation. http://youtu.be/yVRlSsJwD0o https://youtu.be/vmPr3oTHndg https://www.youtube.com/watch?v=_GtzTT9Pdl0 https://www.youtube.com/watch?v=ABqKPz28e6A https://www.youtube.com/watch?v=rLZ49Jce_n0 https://www.youtube.com/watch?v=XvAsz_ilQYU https://www.youtube.com/watch?v=K8tMHiX9lSw https://m.youtube.com/watch?v=dxwjPuHIV7I https://vimeo.com/201482507 https://www.youtube.com/watch?v=ZSixqL0iyHw |
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14th Dec 2014 3:42pm |
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