93 Wrangler Clutch Problem?

Hav'n a problem switch'n gears on my 93 manual trans with 67K miles. When I start the car, I can't switch gears when I push in the clutch peddle. For example, all I hear is gear thrashing when I attempt to engage reverse. Same with other gears at startup. I can turn off the engine and engage a gear, start the engine and all is ok - for that gear. However, after the car has been on for a while ( I drive it around in a low gear for 5 -10 minutes ), I can switch gears rather smoothly, as if there is no underlying problem! The clutch peddle does seem a tad bit loose although I really can't remember if this is a recent development. Also, the clutch hydrolic level seems to be ok.

Any ideas?

Roger

...I was incorrect in my statement that the clutch hydro fluid reservoir was full. I added a few ounces and the clutch appears to be working like a champ!