3 on the tree slipping?

[73kay]

Hey guys, joined a little bit ago but first time I have had a chance to post. The last time I was driving my truck, I noticed the transmission slipping bad as I shift. Gets to a higher rpm once the I engage the clutch, but as the truck speeds up and it finally catches. I was just surprised because I didn't get any warning or heads up that the clutch was going bad.

I got a 76 shortbed i6 250 with a 3 speed on the column and I was hoping to get a little more life outta it before I drop a crate 350 in, but I guess that project is moving up fast. I might as well rebuild the column shifter while I am at it, I read some good stuff earlier, but I just want some general thoughts on what you guys think. Does it sound like the clutch is gone? I don't hear any odd noises etc. Appreciate your insights. What should I replace while I have it apart?

Thanks guys!
Andrew