cant get the diff's to lock

[bpenn1980]

If this is repetitious I apologize, but I just want to make sure I'm doing the process correctly....never had a truck with lockers before.

Sitting in Park, idling. Drop small stick to Neutral then to Low. Center Diff light and ABS light both come on. I'm good to this point. I can drive in Low and it "feels" engaged. The problem is getting the rear and front diff's into the game.

Put it back in Park. Center Diff is still locked. Push dial and turn to the first click. Rear Diff light starts blinking, but doesnt go solid. I cant remember exactly if I can hear the click from the glove box when I turn it on or off, but I get a click sound which I assume is a fuse of some sort.

Turn dial further and Front Diff light starts blinking. Same deal. Wont turn solid and handling is perfect, so I know its not engaged. I rolled slowly forward, then in reverse. Nothing. Roll forward in slow left hand turn, slow right hand turn, reverse both of those, still nothing. The rear diff did actually engage, but getting it to disengage was not easy. EDIT: If you are doing this for the first time don't be a schmuck like me and test it on asphalt

Granted, I was on asphalt (no no I know), but I was going very slowly and not turning more than described above.

Anyone have any ideas?

Brad

 

[elmariachi]

First off, don't test it on pavement. Second, if they haven't been frequently used, they will often be hard to lock. They need exercise before assesing that you have a problem. Find some hills (any of those in Cali??), twist the knob and climb. Toyota will do the rest.

 

[94cruisercal]

When I got my truck I had the same experience. Take it to some dirt and repeat the process you just described. It should loosen up the actuators before long and then you need to repeat this procedure often to keep them working smoothly when you need them. Others with way more experience will chime in and give you sage advice but thats my $0.02

 

[bpenn1980]

I'll be in Big Bear for 4 or 5 days over Christmas so I'll have plenty of dirt to exercise them on. Hopefully that does the trick and I wont have revive this.

 

[BooKilla]

should have got the factory arb air lockas

 

[gray]

Ditto for me; CDL locks up fine in low, but front and rear locker lights just sit there and blink. Can anything be harmed by letting them blink as long as you are on dirt, grass, gravel, etc; or, can you burn something up ie: motors or relays by trying too long to get them to work? From what I recall, you can burn up the CDL motor if that is not engaging, but you keep trying??

 

[MikePL]

Maybe you should have a look at the diff lock actuator before you do the birf job. It's fairly accessible from underneath the truck. I do not recommend taking it apart as a first solution because there is some fiddling with small parts (although the whole assembly is simple. So maybe take it off the truck and try to apply lubricant to it. Work the motor back and fort and it should work. It is common for these actuators to get stuck if someone 'abuses' the truck (abusement = flat pavement driving) instead of mudding it like the normal guys. But once the actuator breaks free it will work with no problems.

 

[bpenn1980]

Update:

I can hear a "tick tock" click noise from the passenger side cabin when I turn the dial to the 1st mark, rear lockers. If I turn it again to the front lockers I dont hear the noise. I'm trying my best to get up to speed on this and read A LOT of info from past posts today. Is this the relay?

I have the FSM and am actively attempting to diagnose this, but any help you all can add is much appreciated.
Brad

 

[mkfour]

You need to find some dirt and engage them there to find out if they don't work.

If they don't work I've got a broomstick we could shove inside. Not too sure if it'll work, but it's worth a try.

 

[bpenn1980]

Update:

Went out to a dirt lot and got the rear to engage every time I turned the dial. Front is still a no go. I've listened closely under the car for sound of the motor and cant hear anything. Also, hit the actuator a few times with a 16oz rubber mallet just in case. No joy.

Again, there's a click (like a double click, "tick tock") from the glove box when I engage the rear locker, but no click when I turn the dial to the front lock position. I've read about people who call this "click making device" a relay..cant find anything in the FSM

I crawled under the truck to see what I could see. Man I hate electronic stuff. I couldnt find the diff lock switch (unless its the same thing that has wires coming out of it on the actuator). I found a really dirty connector running along the top of the front axle to the differential, but couldnt see where it terminated. Couldnt unplug it and clean. Wouldnt come apart easily, so I didnt want to damage it quite yet.

There was a tube or wire sticking up about 2-3 inches out of the actuator. Seemed out of place, but what do I know.

I'm referencing the FSM section SA-136...confusing stuff
I'm realizing that I cant read wiring diagrams

 

[bpenn1980]

You need to find some dirt and engage them there to find out if they don't work.

If they don't work I've got a broomstick we could shove inside. Not too sure if it'll work, but it's worth a try.

Depending on timing this weekend, maybe I'll try and pull the actuator since its right there. FSM shows it to be a connector, tube, 2 nuts and a bolt to remove....never that easy though

 

[mkfour]

I took a look at he FSM. It states :

"If the gears of the differential lock system are not meshed, the indicator light remains blinking, so rotate the tires to mesh the
gear."

I'll guess and say that they mean to jack only one tire up and manually rotate the tire an arbitrary amount. Even from normal operation I could see that one side would become radially displaced from the other causing delayed engagement. This could explain why some have experienced slow engagements for no apparent reason.

This could also explain why "exercising" you lockers helps them to engage faster, by keeping them in sync on a regular basis.

But I don't see how engaging the locker while driving straight allows the axles to sync together. It seems as though you would have to turn one direction or the other.

Removal seems fairly easy and it seems as though you can test the actuator with two 1.5 V batteries in parallel. I would also assume that you could check the connector (sending unit) that it is delivering 1.5 V with the dial on FR-RR.

 

[FJBen]

Update:



There was a tube or wire sticking up about 2-3 inches out of the actuator. Seemed out of place, but what do I know.

thats the breather tube. If thats just open and hanging, it's a good chance that actuator is full of crap and rusted shut. Thats what happened with my rear actuator. If you look at the end of that, you should notice it's a tube with plastic sorta wrapping around it. Usually the rear mucks up first as it's always getting sprayed from the front axle.

You can pull that actuator off fairly easily and then test to see if the armature moves any with a 9 volt battery. If it doesn't work there's a good chance it's just rusted shut.

THere are some threads detailing taking it apart. I would try that first to see if you can clean it. Just be careful as there is some spring clocking that needs to be correct. Mine was rusted shut which is strange as there was no rust anywhere on the vehicle or frame...just water getting into the actuator from rain/snow. I got a used one from Cruiserparts.net that worked fine for about 1/3 the price of new.

hope that helps.

 

[bpenn1980]

I found this thread where Tools R Us discussed the "4x4 Control Box" as being the culprit.

https://forum.ih8mud.com/showthread.php?t=55204&highlight=front+locker+click

His issue appears similar to mine. Anyway do you know how to locate this box and whether its possible to repair or do I need to replace?

The FSM doesnt show where this box is, or rather shows it as the "ECU" in the engine compartment on DS...??? Pulled glove box yesterday night, but there's a lot going on in there and I couldnt locate it.

Brad

 

[FJBen]

I found this thread where Tools R Us discussed the "4x4 Control Box" as being the culprit.

https://forum.ih8mud.com/showthread.php?t=55204&highlight=front+locker+click

His issue appears similar to mine. Anyway do you know how to locate this box and whether its possible to repair or do I need to replace?

The FSM doesnt show where this box is, or rather shows it as the "ECU" in the engine compartment on DS...??? Pulled glove box yesterday night, but there's a lot going on in there and I couldnt locate it.

Brad

If you pull that panel at the passenger floorboard, you'll see a black box. two plugs going into it. At the time I had another 80 series with lockers so I switched boxes as the lockers worked fine on the other cruiser. Same thing happened so I eliminated that ECU box.

I think the click only occurs when power can go to the unit and the acuator "wind" the spring. If it can't wind that spring, I don't think there is a click. Easy test would be to find an 80 with lockers ;p and switch boxes...

apparently there are some tests in the FSM to test that black box. I don't know them.

 

[Tools R Us]

OK, it's been a while, but maybe I can shed some light.

Your center and rear are working, so the circuit has power and we can assume the CDL sensor is working. So that leaves the front part of the circuit. The power comes from the switch to the Diff. lock ECU (this is what it’s called in the FSM) or the 4x4 controller (IIRC something like this is the name on the box) it’s in the right side kick panel. The relays in the box that control the actuator motors are activated by power from the switch and IIRC ground from the limit/slider switches in the actuator. So those are the first two things to check.

Pull the right side kick panel and unplug the box. With the key on, the CDL locked and the front locker switch on, you should have battery voltage at terminal #6 black-green wire on the wire harness plug (see pic). With the actuator unlocked you should have chassis ground at terminal #16 the blue-yellow wire and terminal #14 the blue-black wire should be open. This is IIRC it maybe the other way around, but one of them should have ground and the other open.

If the above is true the relay should click, sending power to the actuator motor. If there is no power to #6 you have a problem with the switch or wiring between it and the box. If there is no ground on #16 (#14?) you have a problem with the limit/slider switches in the actuator. In my experience the most common problem in this scenario is moisture getting into the actuator and fouling the switch contacts. Most of the time this can be solved by disassembling the actuator, cleaning and greasing. Most of the time if there is moisture, there is also rust on the gears, motor parts, etc, if it's been there a long time the actuator my be junk, but I have been successful in repairing all but one of them that I have done.

If your going to dive into the actuator read all of the threads on it, timing is somewhat tricky and understanding how they work makes it much easier. When you put it back together seal it up good, moisture is what kills them. I use silicone sealer, but any of the good form in place sealers would work. The hose your seeing is the breather, it should be inside of the wire harness. I would get some vacuum hose and run it inside under the dash, somewhere with the least chance of getting moisture into it.

 

[bpenn1980]

Thank you Tools R Us! I'll get in there and do those tests plus whatever is in the FSM.



ps- was planning on routing the diff breathers to the engine compartment and sticking a fuel filter on it to keep the air clean. I'll run the locker breather up there as well since that seems to make sense.

 

[bpenn1980]

Pull the right side kick panel and unplug the box. With the key on, the CDL locked and the front locker switch on, you should have battery voltage at terminal #6 black-green wire on the wire harness plug (see pic).

Check, RF(#6) to GND(#13), 11.9v

With the actuator unlocked you should have chassis ground at terminal #16 the blue-yellow wire and terminal #14 the blue-black wire should be open. This is IIRC it maybe the other way around, but one of them should have ground and the other open.

I'm not sure what "open" means, but this is what happens w/ CDL light on and RR and RR FR on the dial.

R3(#16) to GND(#13), 0v
R4(#14) to GND(#13), 0v

R3(#16) to R4(#14), 0v
R4(#14) to R3(#16), 0v

IG(#8) to R3(#16), 0v
IG(#8) to R4(#14), 0v

RF(#6) to R3(#16), 0v
RF(#6) to R4(#14), 0v

Everything coming to the ECU is good though (or what I think is good since I dont really know)

IG(#8) to GND(#13), 11.69v
R(#12) to GND(#13), 11.69v
RF(#6) to GND(#13), 11.69v
RLP(#2) to GND(#13), 11.5v
FLP(#9) to GND(#13), 11.43v
4WD(#15) to GND(#13), .04v
SPD(#4) to GND(#13), .05v

-----------------------------------
I think the relays are ok though they were my concern initially since I cant hear them click. (see next paragraph)

I checked the R1(#10) and R2(#11) (rear relays) and the R3(#16) and R4(#14) (front relays ) by grounding them to GND(#13) with the ECU plugged in and going through the dial (if my methodology is off, please correct me):

OFF to RR: R1 to GND spikes to 11.3v then drops to 0v.
RR to OFF: R2 to GND spikes to 10.9v then drops to 0v.

RR to FR RR: R3 to GND spikes to 11.3v then drops to 0v.
FR RR to RR: R4 to GND spikes to 10.9v then drops to 0v.
---------------------------------------
OK, wrapping up here folks, here is where I think the problem is, but I need some of your insight to interpret the test results
---------------------------------------
---------------------------------------

On page SA-143, the FSM has me test the front and rear actuator motors. Says if the "circuit is not as specified, replace the ECU", but I wanted to run it past you. Plus, who knows, this may be useful to somebody down the line.

Rear test:
(this is my base since the rear works and I can hear the motor when I turn the dial)

Idea is that when the dial is turned from OFF to RR (for the rear) the M1(#3) to M2(#1) will spike to 10-14.5v (mine spikes to 10+v). Then turning the dial from RR to OFF should spike the M2(#1) to M1(#3) connection will spike to 10-14.5v (mine spikes to 8+v). Though the M2 to M1 voltage is low, I hear the motor during both tests.

Front test:
Turn the dial from RR to FR RR should spike the M3(#7) to M4(#5) to 10-14.5v (mine is 0v). Then going the other way from FR RR to RR should spike M4(#5) to M3(#7) to 10-14.5v (again, 0v).


For kicks I did the same test, but grounded each motor connection instead of hooking them up to each other. I got the same exact result.

If you've made it this far you, a) deserve a beer from me, and b) hopefully know what the hell I'm talking about because I'm getting pretty well confused

 

[bpenn1980]

Forgot to ask something.

Do you think it would be safe to try putting a 9v battery to the motor connections? For instance, I'd connect the positive side of the battery through a wire to M3(#7), turn the dial from RR to FR RR and see if the motor sounded off. I suppose I'd have to be careful not to leave the battery connected though so the motor wouldnt burn out.

Anyway, its late and I'm delirious with M1 R4 #16 GND M3 11v ECU

Time for another and some sleep

 

[98 SNAKE EATER]

Before you get too involved with the wiring, I suggest putting it on a lift or jackstands and try to lock them in the air...

Sometimes there needs to be a large difference in wheel rotation for them to engage, so while idling in Drive in the air, just slow one wheel down by hand and it should lock

There are times when mine will lock instantly and others when they will only lock after a few sharp turns in the muck...

They have never failed to engage when I needed them though

Some lockers (non-OEM) require more than a full wheel rotation difference before the lockers will engage


Yours is probably just sticky from lack of use...