Diff Lock

Could someone please clarify the operation of the Diff Lock on my 2004 Discovery please. Is it a true diff lock similar to the after market air operated diff locks that give you 100% traction to all wheels when engaged.

I understand the basic operation of the transfer lever from high range to low range for better traction but what then does the diff lock do different to low range. Does this mean that in normal low range you do not have good traction compared to diff lock.

The manual does not clarify this very well.

regards Martin

The diff lock on a standard, factory vehicle works by locking the front and rear drive shafts together. There are three diffs, one on each axle and one between the two drive shafts. Without the diff lock engaged you will be able to loose drive with just one wheel spinning (i.e. on ice or mud), however, with the diff lock engaged you provide constant drive to both the front and rear axles, which means that should one wheel start to spin you will still have drive on the free axle. Should you have two wheels spinning, 1 front and 1 rear, you will still come to a halt, which is when aftermarket cross-axle lockers come in.

One warning though; do not drive great distances with your diff-lock engaged. This creates 'wind up' in the system, which can lead to catastrophic (and expensive) failure. Only use the diff-lock when you think you are likely to loose traction, knowing this comes with experience.

Hope this helps.

Chris

thanks chris

Your explanation is surely better than the one given by Landrover in the owners manual. You could imagine the trouble I could of gotten myself in if I believed I had true locking diffs.

Think about the two types of Diff. Lock as 'Centre Diff Lock' (the one you have).
and 'Cross Axle Diff Locks'. (the ones you don't).
Cruisermik.

thanks

brilliant explanation chris, that helped my understanding of it too....

No worries, glad to help out


Chris

Hi just thought i would ask as diff lock was not fitted as standard to 2004 model disco,because thet did not feel the need due to great traction control system fitted,can you get your car to go into diff lock is there a light on the dash or is it just high/low to the left, the manual and sticker on the gear tunnel is misleading as some cars had sticker on it that says diff lock but may not have linkage fitted,tiga

On some later series 2 discos, when bought from new there was a factory option to have it fitted or not, just have a play around with the smaller stick if it has one as im not sure but if you engage diff lock, a light will apear on the dash !!!

best explanation i have heard wel in mate thanks.

Newbie

Would diff lock be required for sand? i often take mine to the beach for a drive over the dunes etc. I allways put it in diff lock.

Just to add my two penny worth...

There is a diff lock warning light on the dash. The ability to lock the center diff was included when the Disco 2 was launched in that the 'spigot' was still fitted on the top of the transfer box - this was, after all, carried over from the 300 series Discovery. Later models (from about 2000, I think) lost the spigot but the parts could be retrofitted if required. For the last model release, i.e. 2004 model, the lever was once again included as a standard fitment.

One thing to watch. If you stall the car and diff lock is engaged, once restarted, ABS and TC will not be enabled and the warning lights will stay on. This is normal operation and can be over ridden by modifying the wiring (cut the signal to the computer).

Diff lock kits are available from a couple of suppliers in the UK if anyone is interested. Discoparts retails a solenoid controlled setup, Ashcroft Transmissions sells the genuine parts (as fitted to the '04 car). Ashcroft can also supply the parts needed if the 'spigot' is missing.

As has already been mentioned, engage diff lock only when needed. There are times when the TC isn't up to the job - for example in good old sloopy mud, diff lock will stop TC getting carried away with itself!

Tony

Many thanks Chris, after reading your explanation about diff locks standard and retro fitted cross axle locks you have given me the info i need to sort out some of our off road club members who argue (!) that standard diff locks give true 4 wheel drive.

Fitting a centre diff-lock to the Disco series2 greatly improves off-road capability of this vehicle, even though it has got traction control. Another point, it is important to know what this "diff-lock" in a landy is as Chris explained it. Other 4x4 owners tend to see this centre diff-lock as a real axle diff-lock which leads to comments like "that was good but he has got a diff-lock" or "he would not have made it if he did not have a diff-lock". But now you can point out that is actually just the same as any normal 4x4.

When using a Diff-lock in sand it is important to remember that when turning there is no slip between front and rear axle, this causes the 2 wheels with the least traction to dig in. When driving straight or climbing a dune it will help to engage diff-lock.

I was told best to fit centre diff lock as the TC works on the brake discs which means it does not work when going through water more than a couple of inches deep as discs are wet ect? Any comments?

regards

Dave

That was the best explanation of how diff lock works that I have heard Chris, Thanks I feel all enlightened now.

tigapiglet said:

Hi just thought i would ask as diff lock was not fitted as standard to 2004 model disco,because thet did not feel the need due to great traction control system fitted,can you get your car to go into diff lock is there a light on the dash or is it just high/low to the left, the manual and sticker on the gear tunnel is misleading as some cars had sticker on it that says diff lock but may not have linkage fitted,tiga

Click to expand...

Hi all, I've just registered and so bear with me until I get familiar with your forum, thanks.
In ref to the above, I've just bought a 300Tdi (manual, previously owned an auto variant) and after selecting the difflock to negotiate a fairly steep but short climb on some green lane banking I noticed that when disengaging back to normal onroad driving that the dash light didn't go back off. The diff was engaged literally for about 15 seconds, stopped the car and pulled the lever back to the high ratio setting. Should I have any reason for concern?
Also, since my very small adventure I have now become aware of a knocking sound which I haven't yet had time to investigate. The sound was very much like a wheel bearing knock when putting load on a wheel, ie turning to full lock and gently creeping forward. It also did when pulling off in a straight line.
I can't imagine it's anything serious (hoping more like!) as the offroad experience was nothing more serious than pussy footing about on some countryside common land.

What a ramble for a first post eh?

Thanks.

the delay in difflock is quite common reversing up will sometimes clear it. for the knocking have you chacked you haven't got a stone or clump of grass & mud caught up anywhere

difflock hasnt disengaged - yu are winding up the transmission. - drive it backwards fur a 100 yds or so until it disengages. You may need to do this several times, till it works.