Diff lock problems, any ideas?

Hi

I've recently aquired a '88 defender 90 which is generally very tidy, however the diff lock does not seem to work.

The gearstick will move over into the correct position and will still transmit power either in high or low ratio but does not lock the wheels, i've also noticed rather a lot of oil eminating from around the bell housing area, could this be related?

Basically if anyone could point me in the right direction towards finding the cause / fixing the problem i'd be very gratefull.

Thanks

Josie

Cobden said:

Hi

I've recently aquired a '88 defender 90 which is generally very tidy, however the diff lock does not seem to work.

The gearstick will move over into the correct position and will still transmit power either in high or low ratio but does not lock the wheels, i've also noticed rather a lot of oil eminating from around the bell housing area, could this be related?

Basically if anyone could point me in the right direction towards finding the cause / fixing the problem i'd be very gratefull.

Thanks

Josie

Click to expand...

Dif lock locks the centre dif not the wheels.
The diffs on the axels remain as...diffs, ie one wheel will spin. Full dif locks on axels is a different ball game.
LSD on axels is a good system but it makes off roading interesting in mud as you have to power turn as well as steer!

Bell housing oil is not going to be related, its either engine oil or the main geabox oil.

As said above it will not lock the wheels, only the front and back axles so that you dont end up with all your power being lost when your back or front wheels are on a bad surface and loose traction.

If however you still suspect your centre diff is not locking then you can take the middle seat cover off, and underscrew the metal panel, then look under and towards the front of the car (or crawl under and have a look but its on top so for the sake of 4 screws its easier) and you will see a lever that should move when you move the transfer box gear stick from side to side, make sure that the movement moves right down through all the links and moves the little bar its connected too.

If its physicaly is not moving then its seized through lack of use.

Is the light coming on? If the light is just not coming on then the wiring/switch/bulb could be gubbed.

Thank you very much guys for your advice, shows how little i know (i'm too used to driving tractors where the diff locks all 4 wheels!), i will check that the lever is moving when the transfer box gearstick is moved.

The light is not coming on, but then none on the left hand side of the panel below the instraments are (e.g. handbrake warning light etc.), are they all fed from one fuse?

I'm pretty certain that the oil is engine oil, any suggestions as to where it could be coming from? i've had a good look underneath and above the engine but nothing obvious!

Thanks

Josie

I would guess crankseal may have gone to cause the oil to leak out there. If it is it's engine out job. Got to do it on the wifes 110 on Friday, and I ain't looking forward to it either.

Can a jammed diff lock switch prevent you selecting diff lock? My 300tdi would not select at all as the whole lever etc was seized due to lack of use. Got the lever moving but no cdl and no light. I've been told that the problem is the switch being seized.

What do you reckon?

BTW Brad if you want some advice on how God does speak to us feel free to ask!

Nah highly unlikely for the switch to stop the difflock engaging switch is tucked away under the High low operating lever, and is a spring loaded plunger type thing.

Don't seem to be able to find any pics of the crankcase seal. Though if your replacing it I'd think about replacing the clutch and arm and the bush that the gearbox input shaft sits in while your at it.

The oil leak could also be the joint between the clutch housing and cylinder block. If you look at this put some sealant on the bolt threads when you bolt it back up 'cos oil can leak down the threads from the crankcase.

That's fantastic, thanks very much for all the advice guys.

I'd prepared myself for an engine out job, think i'll steam clean the underside, double check to see if i can see where the leak is coming from and take it from there!

Thanks once again for all the help.

Josie

If it's the crancase oilseal then most of the oil will be coming out of the drain hole in the bottom of the clutch housing if it's the joint thats leaking then most of the oil will be running down the front face of the housing.

Either way it's the engine or transmission out to do it, unless you can live with it.

Thanks, i'll take another look at it this afternoon. I've got some time off in a couple of weeks so guess its time to borrow my dads engine crane and get the engine out for further investigation and fixing of the problem

Thanks once again.

Josie

Ps. i have some other mechanical based questions but i'll start a new thread!