Front & Rear Diff Lock Operation

[daveymg]

Hi all,
i've just purchased a 1995 LC VX, 1HZ engine, jap import. It has the front/rear diff lock selector but I'm not seeing any indicators when I select either lock setting. I've found a YouTube of a series 80 that shows a red indicator that flashes for each of the locks when they are selected and then go solid when the locks engage. From the vid it looks as though both of these indicators light up momentarily when the ignition is turned on. So, I'm not sure whether my diff locks are functioning. The centre lock and abs indicators light when the transfer is shifted to low, but no front or rear. I can't hear any actuator type noise either.

What's a good starting point troubleshooting this? Does this model have the dash indicators? Are there fuses for the actuators?

Thanks for any pointers.

Dave

 

[AndyCook]

Hi and welcome!

have you been trying in low range.
Also if no light comes on - on dash when ignition turned on - i would aslo check that there are actually accuators on the axles!
i have seen an import 80 before that had difflock switch installed on dash, but owner had never fitted the accuators!

 

[daveymg]

Hi and welcome!

have you been trying in low range.
Also if no light comes on - on dash when ignition turned on - i would aslo check that there are actually accuators on the axles!
i have seen an import 80 before that had difflock switch installed on dash, but owner had never fitted the accuators!

Hi Andy, thanks for your reply. Yes, i've tried in low. Hmm, no actuators isn't a possibility I'd considered, is there a visual check I can make to confirm?

 

[AndyCook]

photo of rear one here on axle
http://www.landcruiserclub.net/foru...53-Rear-diff-lock-actuator?highlight=difflock

and there should be something similar on front axle, on rear of diff, with wires going into it

 

[daveymg]

Cheers, will go crawling shortly, once it's daylight!

 

[daveymg]

Couldn't wait, took the torch, there are definitely actuators on the front and rear axles. Maybe this model locks everything in low range? I'll try jacking a wheel up and testing when/if it locks.

 

[AndyCook]

you are up early - its only just got dark in Scotland!

hopefully someone with an 80-series will help?
I have a 90-series which just has a rear difflock and the dash light breifly comes on when i turn key in ignition, and when i activate locker, when in low range/centre diff locked, it flashes until engaged and then light stays solid. i can also hear the accuator if engine isnt running.
try jacking up back axle to see if it engages - you will need both wheels in air when centre diff is locked, since if you just jackup one wheel you wont be able to turn it by hand due to centre difflock

 

[daveymg]

Ok, thanks for the advice. Yep, early riser plus it's daylight saving now.

 

[daveymg]

Did some tests and exercised better powers of observation. Turns out I DO have the f/r lock indicators, they light up when the ign is turned on, just that they are on the opposite side of the dash from the cdl indicator so wasn't looking there.

With both lhs wheels jacked up, auto in N and transfer in N both wheels are free. Setting transfer to L locks the wheels together but they both turn. Setting the diff lock switch to any setting with the transfer in L has no locking effect at all.

So now I'm thinking maybe a wiring problem with the switch or the switch itself? Is there anywhere I can meter out the switch to see if it's signalling properly?

 

[AndyCook]

Did the lights on dash start flashing when you turned dial for axle lockers?

 

[daveymg]

No, no flashing, which is why I'm thinking the switch isn't signalling.

 

[Towpack]

From your description it sounds like your CDL is working OK and the CDL light should glow steady when locked. Check the connectors at the rear of the F&R locker switch and then at the locker ECU. When the F&R switch is operated the ECU sends power to the lockers (and the warning lights) and then waits for the signal from the lock position switch on each actuator, confirming that the locks are fully engaged. From what I can make of the wiring diagram, all the DL warming lights are fed from the same fuse so that should be OK.

 

[daveymg]

Thanks Towpack, will check the switch cabling next. The cdl light illuminates ok when the transfer is in low although it doesn't light up with the ignition switch the same as the f/r lock lights.

 

[daveymg]

Managed to prise off the facia holding the diff lock switch and revealed ... Bare switch, no cable attached. Couldn't see anything loose floating around so will try and remove the lower facia panel and see what's there. I'm hoping its not been disconnected deliberately.

 

[daveymg]

I found the cable floating behind the facia, it looked clean so it hadn't been unplugged for long I think. With the cable plugged in I had both lock lights flashing in H but neither would lock. In L the front diff locks but the rear continues to flash. With the front locked and shifting to H it remained locked, deselecting it required a bit of travelling before it unlocked. I think I've read somewhere that the front won't lock until the rear is locked, which would explain the behavior in H. Presumably they lock independently of each other in L?

Next test will be to listen to the rear actuator to see if it is moving.

 

[Justin_Elliott]

Neither will lock if CDL isn't - so you'll need to be in L or use your CDL switch (if you've got one) in H.

If you turn off CDL (using H or CDL switch) they'll disengage as soon as the locking pin can move - normally after a little travel - best to try this on loose ground, I.e. when wheels can slip a little.

The actutor motor drives a coil spring which preloads a sliding pin, when everything aligns the pin can freely slide into position (normally with a loud click/clunk) - this is the same for engage and disengage.

The rear doesn't know when the front is locked, but the switching is designed to prevent front only being turned on. So if your front is locking and your rear isn't then it's either not engaging or the switch isn't functioning. Easiest way to check this is by jacking one rear wheel and turning by hand once actuator has been turned on to see if does engage or make a noise like it trying to...

I had problems with my rear actuator harness and switch, but most seem to have actuator problems. So tracking the problem down is the next step.

So if nothing's moving you'll need to check your harness or actutor, or if it does then check your switch....

Hope this helps, it sounds like your doing all the right things....

 

[daveymg]

Thanks Justin. Considering that at the start of this thread I was thinking I might not haver lockers at all, I'm presently a much happier camper with just the rear locker to sort out. I'm enjoying travelling the learning curve. I've been testing on grass which seems to have been ok.

 

[daveymg]

I can clearly hear the front actuator whirring when I select and deselect it but no sound at all from the rear and no locking taking place. I'll have a crack at trying to apply 12V to the actuator motor connections.

 

[clivehorridge]

Just one small comment Daveymg, when actuated, mine work but always show the front and rear flashing engagement light. I know it's a pair of faulty switches, but they operate ok.

When the rear is locked, drive round in a circle. The inner wheel will hop/slip visibly (and you'll feel it) in steps. You won't be in any doubt whether it's working or not.

The front is obvious too, because you can hardly steer when its locked

Good luck...

 

[daveymg]

Thanks Clive, yep I've done a fair bit of driving in circles with, I think, every permutation and combination of lock switches and transfer lever
I've also tried hand turning the wheels with the axles jacked up so I'm pretty sure the actuator isn't working. I've decided to try and find a replacement actuator rather than risk pulling the existing one apart and not being able to restore it to working or re-installable order.