Engaging my diff lock

Hi all. Not sure if this is the correct place to post so sorry in advance.

I’m trying to work out my 1998 defender 90 TD5’s differential lock. I have the small gearstick which works in both high and low ranges as well as neural however when pushing it to the left, nothing. There isn’t a pop feeling like when changing ranges and if it’s in neutral on both sticks, and I push the small one to the left and then forward, no resistance is felt if I pull it straight over to the right.

Can anyone let me know if I should have some sort of resistance or physical feedback from the engagement of the diff lock and if all 90s are fitted with one as standard?

That sounds pretty normal. I assume you have the lock light (or should) on the dash?

H to L or back is often notchy or difficult.

Sideways into difflock just feels like a slight drag (my lever is a bit tight anyway) - there is no notchy, clicks, nothing. The light should come on once the lock actually engaged. When you shift out of difflock, sometimes it takes a little bit for it to disengage - you may need to stop or reverse, or turn a bit - that's why you shouldn't use it on high traction surfaces - the drivetrain binds up.

You can shift into diff-lock while driving up to a certain speed in either range.

The diff lock and H&L range lever acts on the transfer box (LT230) which is fitted to the back of the gearbox.
The H and L range adds another gear to the output shafts. Moving the sticks forwards and backwards activates this additional gear. You do not want to change this when you are moving.
High range is the normal position for driving on the road.
Low range is for when you need more power to the wheels and requires the engine to rev much higher to get motion.

The central diff lock is inside the same transfer box and locks the front and rear output shafts together.
These shafts provide drive to the front and rear axle. Although you can engage the lock, it's not really advisable to do this when you are moving either. The only time this is OK is if both axles are rotating at the same speed and it takes a bit of practise to get this correct. To engage the lock you push the stick to the left, to disengage move to the right.
The lock will only disengage when it is not under load, the best way to get this is to stop, or reverse a short way.
As @AllenWorms said when the diff lock engages a light should light up on the dash. There isn't any other 'feeling'.

You can damage the transfer box if you drive with the central differential locked for a long time on the road.
Yes, all defenders have a transfer box with H&L ratio gearing and a diff lock.

Just to be clear moving the stick to the left does not engage the diff lock, it only makes it possible for it to engage when it wants to, hence little feeling.

Thanks for all your comments so far. If I push the lever to the left while stationary in either high or low range, with the handbrake on and in neutral on the main stick, nothing happens. Am I meant to push it the the left and then drive a few meters to allow it to engage?

Jack the front wheel up without diff lock you can spin the wheel, by hand. Put it in diff lock, spin the wheel and it will lock up, take it out of diff lock then spin the wheel and it should then disengage.
If its all working correctly.

Yes, there's no rigid mechanical connection there. There's a splined slider that moves along so as to lock the front output shaft to the diff carrier, effectively locking the diff. But this is moved by a spring rather than a rigid mechanical linkage. So moving the lever in the cab puts a bit of pressure on the spring, so the splined component moves when it is ready, when all the splines are lined up. Similarly, when coming out of difflock, if there's wind up in the transmission, it tends to hold the slider in position and the spring isn't pushing hard enough to move it, so it stays in the diff lock position until you jack a wheel up or drive over a bump that allows one of the wheels to lose traction momentarily and it'll slide back.

To answer your

Gertrudethedefender said:

Thanks for all your comments so far. If I push the lever to the left while stationary in either high or low range, with the handbrake on and in neutral on the main stick, nothing happens. Am I meant to push it the the left and then drive a few meters to allow it to engage?

Click to expand...

Yes, as you drive forward or backwards the lock will engage.
If you are in a situation where stuck in a slippery situation wheel spinning you should put the clutch in before moving the lever left, if you do it will engage with a bang giving the transmission a jolt.
If reluctant to come out just reversing a bit will make it release.

Anaconda said:

Jack the front wheel up without diff lock you can spin the wheel, by hand. Put it in diff lock, spin the wheel and it will lock up, take it out of diff lock then spin the wheel and it should then disengage.
If its all working correctly.

Click to expand...

Perfect I’ll have a go.

On a similar note, this flashing light on the dash has only been coming on at slow speed since I tried moving the small lever into the diff lock position. Just driven home from work and it is now flashing permanently. It’s the exclamation mark one. Any idea what it is at it’s now every time I drive in either direction and whilst in the high range without diff lock

Brake fluid level?

That can be brake fluid, or indicate that the handbrake is on. Possibly also a fault in the wiring. I've had wires separate from the connectors at both the handbrake switch and the brake fluid cap and had to solder them back on.

Brown said:

That can be brake fluid, or indicate that the handbrake is on. Possibly also a fault in the wiring. I've had wires separate from the connectors at both the handbrake switch and the brake fluid cap and had to solder them back on.

Click to expand...

Yes brake fluid reservoir is full so I took the wires off the cap and put them back on with a click. The light never comes on with the handbrake so this is somthing I will need to sort I imagine. The handbrake lever itself never stays fully down and will pop up 1 or 2 clicks as soon as you let of the handle so perhaps the previous owner got round this issue through removing the wiring. It’s not something to be concerned about then and I should be safe driving without causing any damage?

Doubt it is anything to do with wiring, just cable adjustment. Safe to drive as long as hand brake not draging.

Could this light be a low brake pad indicator?

(To prove) If this light stops on when you keep foot on the brake pedal, low pads.activated by small wire in pads touching the disks.

Im assuming that would sound a bit like a flat. That regular brushing sort of noise?

Hicap phill said:

Could this light be a low brake pad indicator?

(To prove) If this light stops on when you keep foot on the brake pedal, low pads.activated by small wire in pads touching the disks.

Click to expand...

Not sure they have such a thing, mine doesn't.

Anaconda said:

Not sure they have such a thing, mine doesn't.

Click to expand...

some models had them fitted. It confused a few people when they used RR classic callipers on the early defenders. You went for spare parts and your pads had wires embedded in them. Yep I cut them off as not needed