Now I searched around trying to fix mine and no one really posted a for certain how to on how to get your diff lock un siezed. This normally stems from lack of use. This can also happen where you try to use it for the first time and it sticks up while engaged like mine did and your left screwed
So this is how I fixed me diff lock. It worked well.
Details 1997 Land Rover Discovery Series 1 216,000kms. Been stuck in diff lock FOR TWO YEARS! Truck has been in the water, mud, snow everything and anything truck has driven through. It was stuck in there when one of the fron half shafts broke, and do get them home he had to ram it into diff lock.
Step one: You realize your diff lock does not work, you begin swearing, yelling, pulling, kicking, shouting and generally being quite rude to the small lever below your cup holders. You go home and say Ill do it tomorrow.
Step 2: you come back and see that it is siezed. Begin by dis assembling the center console. For mine there was a rubber mat I pulled it up removed the boot from the e-brake and the diff lock shifter. Under what I believe is four screws, two on the console near the shifters, and two in the center console. Then grab your e-brake and pull it up as hard as you can. lift the back of the console and guide the e-brake lever. Great you got the console off and your starting to see things. Remove the foam boot and what you should be left with is an exposed rubber boot covering the diff lock shifter.
Step 3: Grab your drill, drill out the rivets that hold the rubber boot in place. once you have lift it off, should have the shift knob already off, now you have exposed your linkage. This is a good start. But the problem normally is not the linkage its the actual shaft in the housing of the shifter, you can spray it with some WD40, deep creep, free all, human semen, blood, tears, and a little bit of margarine. But if your really stuck (which they normally are, this does nothing.
Step 3: remove the bezel around the automatic shifter, remove the plastic cover on the handle, remove the small metal clip with a needle nose pliers, remove the plastic piece that slides when you press the button, put a 19mm socket on there and loosen the bolt inside, and then tug on it till it comes off. (from experience do not stand over it you will hit yourself in the face) lift the plastic cover off. you have exposed it a bit more, you will see 4 Philip head screws, this is a different type of Philips though PZ something Philips may work but it may begin to skip. once that is done you will notive it has become free and you can almost take it out. BUT WAIT THERE IS MORE!.
Step 4: See more rivets under the edge of the carpet on both sides, drill those bad boys out. and lift the metal housing for the auto shifter a bit and you will have enough room for the last one hiding half way under there, drill that out and lift the entire thing up, take the metal plate and pull it towards the dash board and remove it, the housing to the auto shifter is connected with a cable. It is not needed to be removed, just cover it with something so any debris does not fall inside and cause you problems later.
Step 5. to the right of the diff lock shifter is a rod that has a fulcrum point against the transfer case, at the top where it connects to the shaft then connects to the handle you will see a metal spring clip and a pin, remove the clip, take a small brass punch and hammer and begin tapping it, it should come out (DONT LOOSE THAT PIN!) now remove the the 4 bolts on top of the housing next to the diff lock shifter. 3 14's and 1 12mm I believe. Awesome sauce. Now to confirm that its the actual shift take the hammer and tap the linkage in and out of diff lock it should move relatively freely, this normally does not seize. Now take that pain in the ass piece of technology to your work bench!.
Step: 6. Read the following diagram and dis assemble the shifter, but you will notice that the rod is seized in the small housing circled. Great now what should I do, should I give up on life, light the truck a blaze and buy a toyota tercel? First of all dont say stuff like that people will think you have problems. You take that and try and position it in a way where no pressure it placed on the aluminum housing or that piece the shaft goes into, take a big #3 philips and remove the screws, get your punch position and get to tapping with the hammer, you should get a bit of movement, spray some deep creep WD40 or w.e you use on it, let it sit, flip it over tap the shaft back, spray some more let it sit. Wait. Tap it back out, get some light sand paper clean up any corrosion, and tap it again, it should come out, and remove the shaft, awesome now clean it really well with sand paper both that and the fitting it goes into. Once that is done spray it some more with wd40 for good measure.
Step 7: take some grease, put it on the shaft and in the fitting and re assemble, pack the shifter housing with grease and later that side with some for good measure, bolt it back in put the clip back and rod and give it a whirl, it should work better then new, do it 20-25 times to just make sure its working, re assemble it make sure to get a rivet gun and install new rivets and everything the way it does. re assemble, and give it a try you should have a properly functioning diff lock lever, and make sure to regularly pull it in and out at least once a weak to keep things moving.
Hope this helps, thanks for the guidance with other issues I have had guys, your knowledge really did help and I wanted to give back to the community.
What will you do with a properly working center diff?
I will do...
Thanks guys happy wheeling!