Yes it shares the same reservoir as the brakes. At normal level, they share fluid, but if it gets too low there is a divider in there so that if one system goes and leaks out all of its fluid the other can still function. If your fluid is fine then that's not it.
Like watch this, I'd also guess slave cylinder
"You didn't buy it to look at it"
2000 TJ Solar yellow, 3.73, 178k, limited slip D44
2012 GMC sierra crew cab--Daily Driver
2008 jk X 6spd Red Rock---Sold and missed