Yes defenently change it if you found fluid coming out of it!
That silly thing cost me the C6 in my camper last summer..... very last trip of the season, about 3 hours from home, noticed it wasn't operating normally.
RPM's went alot higher before shifting, shifting it's self was still pretty normal though, at the time, I taught it was just the kickdown rod stuck down again, like it was when I bought this thing 12 years ago... so didn't mind it to much.
2 hours from home, started smelling something burning, couldn't for the life of me figure it out what it was, stoped in a truck stop, open hood, checked around, under, no signs of leaks, and no smoke.....
Carryed on, and off the highway, heading towards home (i'm about 2 miles off the highway, 3 sets of lights from highway to home) that's when I noticed a big problem.
Hard high RPM shifts, taking off in 2nd gear, weird shifting. Odd thing is, never slipped....
At the time, had no idea a bad modulator can cause this.....sure learned the hard way.
So I bought a new one, dropped the pan, can't believe I didn't drop dead by how bad that oil smelled, but anyways, fresh filter, and fresh fluid in hopes to save it, but when I came to do my running engine flush, disconnect the feed while, fired it up, nothing coming out..... pump died.
So I left it like that, and drove it like that to winter storage (10 miles) and got me there no problem, hard high RPM shifts, but still no slipping...
Next season I have to drop the trans and rebuilt it though.... poor thing, a short life of only 150k miles. Even if it has been pulling 12k lbs since new.....