97 mazda protege clutch fluid

[facefrench@gmail.com]

I have a 1997 Mazda Protege LX 5 speed. All of a sudden, when I drive the car around or even have it in cruse control the rpm's will quickly rise. They will keep increasing until I hit the break or let go of the gas or put the clutch down. I am thinking that it may be low on clutch fluid/grease. I know that to add fluid I must take off the speedometer cable, but the question is is there a way to check the fluid level? Also do you think that this is a probably cause? Also does anyone know if it uses fluid or grease?

Thanks