I've got a 2003 Disco with 138k on the clock. I was driving on the interstate around 65mph and it suddenly jumped into N without moving the H/L shifter or the Trans shifter. After coasting it to a stop, I couldn't get it to move. I finally got it to move, but the transfer case is clearly in Low as it will not go more than 10mph. After taking the console out and drilling the rivets for the inspection panel, I can clearly see that the selector is in the H position. Is it possible for something to come loose in the transfer case causing the lever to lose the proper indexing? I also have the "Transfer Case in Neutral" light on in the dash panel.

 

Transfer case being in low range won't keep it from going over 10mph.

Sounds like tranny issue

 

It's not that it won't go more than 10mph, you just have to to run it at a higher RPM than normal to achieve that speed.