I have heard it said there are no dumb questions. I am about to break that rule. I have just recieved a 99 Disco2 ( 170 K ) without any books. What does the green gear with the S in the middle on the dash cluster mean?

 

"sport" The similar M light means manual.

If you download rave from HERE, you can get the owner's manual in PDF. It has the service manuals too.

 

When you hit the mode button when in high range, the sport feature improves the shifting points on the tranny.
If in 4wheel lock, high or lo and you hit that button, the M shows up and you can lock your tranny into any gear you want while wheeling.

 

Since you just got the truck and it has no owners manual you must know that these trucks REQUIRE premium fuel, thats means 91 octane or higher.

 

Wow great response time. Good information, thanks.
The only thing I have that doesn’t take high-test is my wife’s Caddy.