Squeaking Manual when changing gears

On my SR5 Manual (5 speed) if I have the window down, I can hear a squeak when I push the clutch down to change gears, like say from 1st to 2nd. Is there a point that I need to lube to prevent this? It's not a huge issue, but annoying when I knew that something needs some grease.

 

Is it only when you move the gear lever, or does it squeak with the clutch pushed in?

 

Just when I push in the clutch. Once it bottoms out, it stop. When I let it off, it squeaks when it goes back. I can only hear it outside.

 

Outside of the truck, its a hydraulic system from the firewall to the transmission. Best guess is it's the slave cylinder (doubtful) or where the fork is pivoting (best guess) pushing in the throw out bearing against the pressure plate. Does it do it with the truck running and with it off? If it does it both ways see if you can climb under the truck while it's off and have someone push the clutch. It should be coming from the area around the slave cylinder as the fork pivots pretty close to there.