Whine

Hi guys! Doing an engine refresh, so thought it'd be a good time to check out a bit of a whine I had occasionally.

Always the same scenario. Car cold, put in reverse or first...and just as I let the clutch out I would hear a whining sound. Goes away in a minute and won't do it again until the car has sat overnight.

Thought it might be the pilot bushing, or throwout bearing, but everything LOOKS great.

Any thoughts?