Land Rover Repair: Disco rolls after placing in Park, gentle slope, spring mechanism

Question
John, I own a 1996 Discovery.  The former owner sold it to me wholesale because he thought the trans. was going bad and too expensive to fix.  When I put the Disco in Park, the trans. locking mechanism clicks as the vehicle begins rolling.  Even a gentle slope requires the parking brake which I have adjusted after reading your post.  Thanks for that post too, very easy to adjust the brake!

How do I adjust the mechanism so the vehicle will not roll in park ?  I'm told there is a lever and spring mechanism that can be adjusted on the outside of the trans. I plan to fix it myself if I can when we get a warm day next week. Thank you!!

Answer
The only thing you can do from outside the transmission is make sure the cable is shoving the selector lever all the way into park.  You can see that on the side of the gearbox.

If it's going all the way and still clicks, the park pawl is broken and you'll have to remove the transmission and transfer case, then separate the transmmission and tear it down for repair.