Well...I just bought a used Discovery SD. Unfortunately there is no owner's manual cause I'd love to read it! I've never owned a 4wd vehicle.

What's the difference between the Low and High and Neutral on the differential. I drive a lot on the highway...is there one that is better than the other?

 

Not to sound wrong, but you do need to buddy up with another Rover friend or at least someon who has a 4wheeler. There is much to learn and a little hands on learning will do you well.
Low range is used when off the road on hard trails, it cuts your gear ration in half giving you more power and traction.
So do you know someone that can spend a little time with you and your truck?
Mike

 

Low will give you a top speed of about 30 miles per hour, the most common problem with them is the lever stops working as most people never have to use low in the whole time you drive it. It is for offroad work or can also be used to help you start moving if you have a very heavy tow, (like when you pull 4 or 5 tons... which again is very unlikely unless it is a working vehicle)

 

My lever hasn't stopped working, but I don't think the people who had the my disco before me used it at all. It is very stiff and hard to move, with no real clear indication of if it went in to gear or if it is in neutral. Is there anything I can do to lube it up or make it work more smoothly?

 

A couple of things, if you go into one of the lock positions there will be an indicator light on your instrument cluster.
Don't practice in town, do it when off the road.
As for making it easier, you can pressure clean the linkah=ge from underneith and lube it. If it is really bad, go threu the console , clean and lube the linkage.
Don't ever try and force it to engage, you can bend the linkage and then you can't shift.
Mike