Rear Locker Issue (not the actuator) (1 Viewer)

[bobbys]

So, I had my 1997 LC in the shop for a few weeks to have some work done to it. While they had it, I had them install a new rear locker actuator, thinking it would fix my issue with the rear locker not actually locking (blinking light). I’ve replaced the sensor and the actuator at this point, but it still won’t lock (according to the dash light). Also, I hear a relay in the dash behind the glovebox when I turn the switch to lock the rear. Any ideas?

 

[LandLocked93]

So, I had my 1997 LC in the shop for a few weeks to have some work done to it. While they had it, I had them install a new rear locker actuator, thinking it would fix my issue with the rear locker not actually locking (blinking light). I’ve replaced the sensor and the actuator at this point, but it still won’t lock (according to the dash light). Also, I hear a relay in the dash behind the glovebox when I turn the switch to lock the rear. Any ideas?

Not sure on the 97s, but do you get a center diff and ABS lights when you shift into 4Lo? (no axle locks engaged)

 

[Mark W]

First determine if it is not locking or if it is locking but not indicating. No point in barking up empty trees.

Mark...

 

[bobbys]

Not sure on the 97s, but do you get a center diff and ABS lights when you shift into 4Lo? (no axle locks engaged)

Yes, it’s in 4Lo, the center diff is locked, and the ABS light is on. I have added a CDL button and done the 7 pin mod too (not really relevant).

 

[bobbys]

First determine if it is not locking or if it is locking but not indicating. No point in barking up empty trees.

Mark...

What’s the best way to test if the rear locker is engaged?

 

[ColoradoCarlisle]

On my old 100 I had to replace a front ABS sensor to get it to work

Is your light on all the time ?

Can you tell if they hooked it up correctly and if its working

Also you probably know this but it won’t engage unless you are on a slippery surface and turning the wheel a bit

Sometimes I had to do figure 8s in the dirt to get it to go

 

[bobbys]

On my old 100 I had to replace a front ABS sensor to get it to work

Is your light on all the time ?

Can you tell if they hooked it up correctly and if its working

Also you probably know this but it won’t engage unless you are on a slippery surface and turning the wheel a bit

Sometimes I had to do figure 8s in the dirt to get it to go

My ABS light only goes on when I engage my center differential lock. Admittedly, I haven’t had the opportunity to try to engage on gravel and do a bunch of turns and such. My attempts were made on dry pavement. I realize that’s not optimal, but my front locker engages just fine driving straight on dry pavement.

 

[Mark W]

What’s the best way to test if the rear locker is engaged?

Engage it on a gravel road or similar surface, and turn tight. You will be able to hear and see evidence of the tires scrubbing and scuffing the surface.

Engage it on a pavement surface (yes it will engage) and you will certainly feel the steering fighting you some when you turn tight and you will feel (often hear) the tires scrubbing.

With the window down you should be able to hear the actuator cycle when you engage/disengage the locker.

If you still are not sure, jack one tire up and see if you can spin it with the locker on, the other tire on the ground and the rig in park.

Mark...

 

[richardlillard1]

Put the key in the on position, lock the center diff, listen for the CDL actuator. Turn the rear locker on, listen for that actuator, turn the front on and listen for that actuator.

To test engagement, Jack the rear of the vehicle up, lock using the process above and spin the rear tires until lock.

Use methods which give reliable data.

 

[bobbys]

I went to a gravel parking lot and did a lot of turning and such. Still no solid light on the rear diff. It seems to be grabbing like crazy, but could that just be the CDL? I really don’t know how much it should be grabbing with just the CDL engaged.

So, question for those who have suggested jacking up one tire to see if it’ll spin with the others on the ground. Since the rear locker will only engage when the center diff lock is engaged, wouldn’t I need to get all four wheels off the ground for this to work?

 

[richardlillard1]

I went to a gravel parking lot and did a lot of turning and such. Still no solid light on the rear diff. It seems to be grabbing like crazy, but could that just be the CDL? I really don’t know how much it should be grabbing with just the CDL engaged.

So, question for those who have suggested jacking up one tire to see if it’ll spin with the others on the ground. Since the rear locker will only engage when the center diff lock is engaged, wouldn’t I need to get all four wheels off the ground for this to work?

No. An open differential will allow one rear tire to spin if it’s off the ground. Once locked it will be bound to the rest of the drivetrain.

 

[bobbys]

No. An open differential will allow one rear tire to spin if it’s off the ground. Once locked it will be bound to the rest of the drivetrain.

I must be missing something. I just jacked one wheel off the ground. In neutral, with everything open, the tire will spin. As soon as I lock the center differential, it won’t spin, which is what I would have expected, because it’s locked to the front wheels, which can’t spin. What am I missing? In my mind, I’d have to lift all four tires off the ground to test my rear differential lock.

 

[lp2k]

@bobbys Chasing this one myself- if you do some searching- it may have to do with the rear axle itself. Take a look at this thread about twisted splines.

Twisted Splines

https://forum.ih8mud.com/threads/short-side-axleshaft-mod.630480/#post-8394974 Note second to last post for s***ty picture and last post for dimensions of second to last post.

forum.ih8mud.com

 

[richardlillard1]

I must be missing something. I just jacked one wheel off the ground. In neutral, with everything open, the tire will spin. As soon as I lock the center differential, it won’t spin, which is what I would have expected, because it’s locked to the front wheels, which can’t spin. What am I missing? In my mind, I’d have to lift all four tires off the ground to test my rear differential lock.

Sorry, it will rotate until it hits the bind from the drivetrain being locked. You’ll be able to sort of rock it back and forth. If it’s locked to the other tire, it won’t move at all.

 

[ProjectsNMotion]

I had what I thought was an issue will my factory rear locker. With the center diff lock engaged, I would turn the axle diff lock switch all the way to the right, and both axle locker lights would blink. After slowly moving forward and turning side to side, the front locker indicator would turn solid, but the rear never would. After screwing around trying to diagnose the issue by turning in a parking lot, I finally just put the whole vehicle up on jack stands and got my multimeter out. Power was getting to the rear actuator, and it was actually engaging the rear locker, but the indicator switch had some dirty contacts in the connector. I cleaned those out and reassembled everything, and everything has worked perfectly since. I suggest you do the same, put the entire vehicle in the air and start narrowing down the issue with a multimeter. Best of luck.

Cheers

 

[bobbys]

Sorry, it will rotate until it hits the bind from the drivetrain being locked. You’ll be able to sort of rock it back and forth. If it’s locked to the other tire, it won’t move at all.

I had what I thought was an issue will my factory rear locker. With the center diff lock engaged, I would turn the axle diff lock switch all the way to the right, and both axle locker lights would blink. After slowly moving forward and turning side to side, the front locker indicator would turn solid, but the rear never would. After screwing around trying to diagnose the issue by turning in a parking lot, I finally just put the whole vehicle up on jack stands and got my multimeter out. Power was getting to the rear actuator, and it was actually engaging the rear locker, but the indicator switch had some dirty contacts in the connector. I cleaned those out and reassembled everything, and everything has worked perfectly since. I suggest you do the same, put the entire vehicle in the air and start narrowing down the issue with a multimeter. Best of luck.

Cheers

Ok. I’ll give this another try tomorrow and see if I can discern a difference. Thanks.

 

[bobbys]

I had what I thought was an issue will my factory rear locker. With the center diff lock engaged, I would turn the axle diff lock switch all the way to the right, and both axle locker lights would blink. After slowly moving forward and turning side to side, the front locker indicator would turn solid, but the rear never would. After screwing around trying to diagnose the issue by turning in a parking lot, I finally just put the whole vehicle up on jack stands and got my multimeter out. Power was getting to the rear actuator, and it was actually engaging the rear locker, but the indicator switch had some dirty contacts in the connector. I cleaned those out and reassembled everything, and everything has worked perfectly since. I suggest you do the same, put the entire vehicle in the air and start narrowing down the issue with a multimeter. Best of luck.

Cheers

Good idea. I already replaced the sensor, but didn’t clean the connectors. If I can determine that the read locker is indeed locking, this will be my next step.

 

[bobbys]

@bobbys Chasing this one myself- if you do some searching- it may have to do with the rear axle itself. Take a look at this thread about twisted splines.

Twisted Splines

https://forum.ih8mud.com/threads/short-side-axleshaft-mod.630480/#post-8394974 Note second to last post for s***ty picture and last post for dimensions of second to last post.

forum.ih8mud.com

I certainly hope this ain’t my issue. If it is, have you been able to source a modified shaft?

 

[ProjectsNMotion]

Good idea. I already replaced the sensor, but didn’t clean the connectors. If I can determine that the read locker is indeed locking, this will be my next step.

If you the vehicle up on jack stands, it's very easy to determine if the rear locker is actually engaging. Once the CDL is on and engaged and you've switched on the rear locker, just turn the passenger's side rear wheel by hand and see if the locker snaps in. You'll hear and feel it, it's pretty obvious.

Cheers

 

[bobbys]

If you the vehicle up on jack stands, it's very easy to determine if the rear locker is actually engaging. Once the CDL is on and engaged and you've switched on the rear locker, just turn the passenger's side rear wheel by hand and see if the locker snaps in. You'll hear and feel it, it's pretty obvious.

Cheers

I’m running 35” tires. I have 8 jack stands and all of them are too short to get my tires off the ground. As is, I have to use a large block of wood for my jack to lift one tire. I obviously don’t have the correct tools.