1. 6 wheeled Disco in Diff Lock: YouTube - Six wheel Land Rover diff lock demonstration by Trevor Alder

2. This is the best demo I have seen regarding Diff Lock and MoMenTum.
Keep your MoJo up if you want to GO: YouTube - How Diff Lock Works and When To Use It

Hope this helps you newbie understand Diff Lock and off-roading in your Disco. Keep up your Mo if you want to Go.

 

The pressed clips at either side of the spring can weaken and splay out over time and slip over the slot machined in the shaft giving no difflock action.

This is another item I was unaware of, maybe someone else who has been inside the T/C can expound upon this item.

 

Just wanted to say thanks on the info and this helped me to fix my diff lock. I was off roading in some swamps in Florida and I got stuck. This is when I learned that my newly purchased 1998 land rover discovery's diff lock would not engage. Thankfully I worked my way out of there with some manuevering but I was really disappointed and my off roading excursions were over. I finally decided to attempt fixing it after reading this and it turned out luckily it was an easy fix. I got underneath the land rover and reached around the transfer case and found that little nut thats connected to the diff lock shifter. I had my brother try to lock the diff while I used a socket wrench to twist the nut and lock it manually. After locking it and unlocking the diff like this several times and greasing it thoroughly it started to shift smoothly on its own. Went and tested it out and everything works great now. I did not have to hassle with taking out the center consel or anything. I am really excited that the diff works and the land rover has a purpose now. Thanks alot. One side note though. When I shift from high to low shortly after I smell some weird burning smell. Any idea what this could be.