I have a 1999 Silverado 4X4 with 185,000 miles on the original clutch. What happens is that the clutch will disengage in cold weather but in warmer weather I can't get it to disengage. I flushed the master and slave cylinders hoping it was air in the system but that does not seem to be it. Is either the slave or master cylinder going bad or is it something else? How do I tell?

Thanks to any and everyone replying to this post.

Dave