Diff lock problem

[Richard Spandit]

Was trying to get home to Surrey from Cheltenham this morning. Accidentally knocked the diff lock knob earlier on and couldn't re-engage anything. I borrowed my father's Disco manual which I presume has the same setup, but it didn't help.

I tried engaging it in gear, out of gear, engine on, engine off, moving slowly, clutch in and out - in 1st gear the car would start moving but as soon as I tried changing up, the gearbox would disengage and the car would slow to a halt. Doesn't sound normal to me, no matter how basic LRs are...

After stopping on a steep hill, in Leckhampton, I managed to get the damn thing to stay in gear and it was fine for the 130 miles home...

Should the diff-lock have a nice positive selection action, with some clunking, as mine had nothing (a bit of ghastly graunching noise when I was moving and trying to engage something...)

[JST]

are we talking diff lock or high low.

assuming talking high/low

have you tried engaging high with the main gearbox in different gears and letting the clutch up out to help ease it in?

if that doesnt work it could be a linkge problem, acess and veiwing of it isint great but you can remove the grearbox tunnel to see it.

[Richard Spandit]

are we talking diff lock or high low.

assuming talking high/low

have you tried engaging high with the main gearbox in different gears and letting the clutch up out to help ease it in?

if that doesnt work it could be a linkge problem, acess and veiwing of it isint great but you can remove the grearbox tunnel to see it.

By moving the lever to the left, I could sometimes get the difflock light to come on, and it would sometimes go off when I moved the lever to the right.

Should it be possible to engage the lock whilst stationary? I'll whip the panel off tomorrow and have a look at the linkage...

[Andy]

the difflock often wont light the light (or fully engage) until the diff moves slightly. when i havent used mine for a few weeks i can drive several hundred yards before it locks. within an hour it locks instantly when used regulary.

sounds like your talking hi/lo rather than difflock though. it often needs to 'clunk' in with a slight load on the box. its possibly out of adjustment so its not fully locking in & popping back to netural when loaded up. thats what it sounds like anyway.

[Diff]

Was trying to get home to Surrey from Cheltenham this morning. Accidentally knocked the diff lock knob earlier on and couldn't re-engage anything. I borrowed my father's Disco manual which I presume has the same setup, but it didn't help.

I tried engaging it in gear, out of gear, engine on, engine off, moving slowly, clutch in and out - in 1st gear the car would start moving but as soon as I tried changing up, the gearbox would disengage and the car would slow to a halt. Doesn't sound normal to me, no matter how basic LRs are...

After stopping on a steep hill, in Leckhampton, I managed to get the damn thing to stay in gear and it was fine for the 130 miles home...

Should the diff-lock have a nice positive selection action, with some clunking, as mine had nothing (a bit of ghastly graunching noise when I was moving and trying to engage something...)

The high/low lever has a neutral position in the middle and is often stiff if not used frequently. I suspect you accidently knocked it into neutral. You will always get graunching if you try to change between high and low when the vehicle is moving, as there is no synchromesh, and a large difference in ratios. Ideally you should only shift when stationary. Difflock is activated by moving the lever to the left (whether in high, low or neutral). There is no positive engagement, but the difflock light will be illuminated, and the difflock engaged, once the shaft splines on the front output shaft/diff line up. This may be immediately, or after a short distance as has been said.

It doesn't sound like you have anything wrong, it just sounds like stiff linkage which you couldn't get properly engaged, hence it popping out of gear under load. You probably just need to spray some penetrating oil on the linkage and work the linkage a bit.

Whatever you do, don't drive continuously with the difflock engaged on tarmac.

Regards,

Diff

[Richard Spandit]

Whatever you do, don't drive continuously with the difflock engaged on tarmac.

I've read this before (and haven't done it) but why does tarmac have such a bearing on it?

Also, without the diff locked, it looks like I can still select high or low ratio - is this just an idler gear being introduced into the gear chain (with low ratio)?

[LandyManLuke]

when you drive, the four wheels don't take equal paths, normally the diffs accomodate for this. when the central diff is locked the front axle and rear axle have to turn at the same speeds. On tarmac, or any solid, non-slip surface, something has to give, either a wheel will 'skip' or something will go bang.

[Diff]

I've read this before (and haven't done it) but why does tarmac have such a bearing on it?

Also, without the diff locked, it looks like I can still select high or low ratio - is this just an idler gear being introduced into the gear chain (with low ratio)?

As LandyManLuke has said, by engaging the centre difflock, the front and rear axles are effectively trying to turn at the same speed. In normal driving, the axles will turn at slightly different speeds, particularly during cornering. This difference in speed is dealt with by the centre diff in the transfer box. When the diff is locked, the axles and props will suffer from 'wind up' on a hard surface which at best will lead to worn tyres, at worst will lead to something breaking. On a loose surface, any 'wind up' is dissipated by the tyres which can turn at a slightly different speed when necessary because of the lower level of grip.

The high/low/diff lock lever serves 2 purposes. 1 is to change between high and low ratios, 2 is to engage the difflock. You can choose to operate in either high or low ratio, with or without the difflock depending on the circumstances.

For example, if you wanted to manoever the landy on a very steep bit of tarmac in a very tight space, you might want to select low ratio without the difflock.

Regards,

Diff

[Gromit]

when you drive, the four wheels don't take equal paths, normally the diffs accomodate for this. when the central diff is locked the front axle and rear axle have to turn at the same speeds. On tarmac, or any solid, non-slip surface, something has to give, either a wheel will 'skip' or something will go bang.

and to add to this, when the diff is locked, on full lock on a gravel surface for example, you'll hear the tyres scrubbing.

You may also notice, that when disengageing the difflock, it won't actually unlock (i.e. the light won't go out) until there's no load on the diff. Sometimes, you may have to turn and reverse to unload the diff until you see the light go out.

On my 110, I have to engage high range with a bit of clutch and then pull it fully into the high position under load or it'll jump out into netural, usually when pulling out of a junction .

On a defender, you can select any combination of difflock and hi, neutral or low range, unlike a series vehicle.