Diff lock stuck help please

I have been having some issues with my LT230 transfer box and gearbox on my 95 110 and have done the usual searches but not quite finding the answers. It started with occasional clunks and bangs when turning at low speeds, such parking or pulling out of junction, that could be felt through the whole car. This got quite frequent for a hundred miles or so, then stopped, I could not see any visible issue and backed off the handbrake in case it was binding. I have since started to sense drag through the drive train when pulling off as if towing and tyre scrubbing as I pull out of junctions. I have tried the following:

I have engaged/re-engaged the diff lock lever. The light does not come on.
I have reversed the car back and driven in circles
I have jacked one wheel up on each axle and cannot turn in either level position
I removed the central inspection cover under middle seat, I could see play in the clevis pin as the clip was missing, the play would prevent the diff lever moving fully to the right without hitting the tunnel. I fixed that but still the adjustment seems out.
Using a big screw driver I was able to manually lever the to the disengage position, the cam on the top of the spigot is facing straight. It is not seized. It moves and clicks freely, in and out.
I sprayed WD40 on the linkage and lever
The diff light is connected but does not work.

I am thinking the sloppy linkage may have been knocked on by one of my kids using the middle seat, the light has not been on and I have been driving it with the lock engaged. I have probably done 1000 miles with it engaged and am concerned it's locked on due to it being a mangled mess inside. I have nt drained the oil and checked but keen to understand if others have been able to successfully unlock the CDL in this scenario. How easily can these transfer boxes be damaged from road use. Any help appreciated.

check oil level and if it drives ok it will be

A possible cause of your problem is the handbrake. Especially if waded it can get full of grit and the shoes start to catch the drum. The expander on mine needed a very thorough cleaning out. If you Jack one wheel up and it spins with the main box in neutral then your diff lock isn’t engaged.

I would follow James’s advise and test to make sure it’s disengaged before panicking about the T-box

Huddy84 said:

A possible cause of your problem is the handbrake. Especially if waded it can get full of grit and the shoes start to catch the drum. The expander on mine needed a very thorough cleaning out. If you Jack one wheel up and it spins with the main box in neutral then your diff lock isn’t engaged.

I would follow James’s advise and test to make sure it’s disengaged before panicking about the T-box

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Thanks for the feedback. If I jack the car up, one wheel off the ground and have the main box in neutral, diff lock lever in disegnaged postion the wheels will not turn suggesting it is on despite the lever/cam on the actual tbox being in the off position. I have also slackened off the handbrake in case there was some binding.
The tbox has a small leak and I regularly check levels. There does feel like there is drag at low speeds, sufficient to hold the vehicle on a slight hill if the steering is turned.

15MAS said:

Thanks for the feedback. If I jack the car up, one wheel off the ground and have the main box in neutral, diff lock lever in disegnaged postion the wheels will not turn suggesting it is on despite the lever/cam on the actual tbox being in the off position. I have also slackened off the handbrake in case there was some binding.
The tbox has a small leak and I regularly check levels. There does feel like there is drag at low speeds, sufficient to hold the vehicle on a slight hill if the steering is turned.

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if you cant turn one wheel when one is jacked up transmission in neutral,then diff locks on adjust linkage so it operates it correctly using the jacked up wheel as the test for in out of lock

jamesmartin said:

if you cant turn one wheel when one is jacked up transmission in neutral,then diff locks on adjust linkage so it operates it correctly using the jacked up wheel as the test for in out of lock

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Thanks. I have been bypassing the linkage and moving the cam/arm on CDL spiggot on the top of the actual tbox and scan't get the wheel to turn. This is why I was concerned there was an internal issue. I will have another go with a wheel off the ground and experiment with different positions.

15MAS said:

Thanks. I have been bypassing the linkage and moving the cam/arm on CDL spiggot on the top of the actual tbox and scan't get the wheel to turn. This is why I was concerned there was an internal issue. I will have another go with a wheel off the ground and experiment with different positions.

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if your looking down on the top of the diff lock spigot turn it anti clockwise to unlock diff ,if it doesnt unlock try rocking wheel or undo the diff lock switch a few turns, if switch is wound into far it jams the diff lock selector,the selector is sprung operated so moving the outside linkage doesnt positively work the selector so you have full movement at the lever but not at the selector fork in the box

jamesmartin said:

if your looking down on the top of the diff lock spigot turn it anti clockwise to unlock diff ,if it doesnt unlock try rocking wheel or undo the diff lock switch a few turns, if switch is wound into far it jams the diff lock selector,the selector is sprung operated so moving the outside linkage doesnt positively work the selector so you have full movement at the lever but not at the selector fork in the box

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I have been out fiddling this morning. The spigot turns anti clockwise, with some pressure from a screwdriver it moves to the point that the wire arm that goes through the flat horizontal arm fouls with the bolt that holds the spigot in position. Still no joy at freeing it up. When you say the diff lock switch, I am assuming this the light switch? It behaving like there is an on the inside not the external linkage.

15MAS said:

I have been out fiddling this morning. The spigot turns anti clockwise, with some pressure from a screwdriver it moves to the point that the wire arm that goes through the flat horizontal arm fouls with the bolt that holds the spigot in position. Still no joy at freeing it up. When you say the diff lock switch, I am assuming this the light switch? It behaving like there is an on the inside not the external linkage.

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yes the switch is just behind the spigot,use a 13mm socket on the spigot nut to turn it

jamesmartin said:

yes the switch is just behind the spigot,use a 13mm socket on the spigot nut to turn it

Click to expand...

Thanks. will report back.

I backed the diff switch off to the point I took it out the tbox but no different. I had a spanner on the 13mm diff lever spigot and tried turning anti clockwise whilst rocking the drivers wheel (jacked up) and nothing. Is it worth looking inside under the side cover held on with six bolts?

The easiest way I have found to check if the diff lock is disengaged is to jack one wheel off the ground and gently try and set off, if the raised wheel spins the diff lock is disengaged. If it tries to set off then the diff is locked. Clearly you need to stop before it falls off the jack.
The thing to remember with the diff lock linkage is that the last part of the internal mechanism is spring loaded, so you can't force the lock in or out with the lever, which is why they can be reluctant to pop out if the transmission is a little wound up.

id take the 3 bolted spigot housing off

If the light switch isn’t working, as above sounds like something isn’t right around the selector. James is a legend so follow his advice, if something doesn’t look right or you solve it don’t forget pictures.

Thanks. I will have time at the weekend to take the floor and tunnel out. Remove the spigot.