the peddle pushed in all the way engages the throw out bearing, spinning the bearing on the clutch fingers, with the rpm of the engine. with the peddle released is disengaged. i would say the pilot bearing is dry and you can hear it squealing. how do you tell if its bad?
I'm assuming this is in response to my earlier post saying the pilot bearing will not make noise with the clutch out (pedal up) - if it is, then consider this, with the clutch out (pedal up) the clutch disc (friction plate) is locked to the flywheel and rotating with it as a single unit.
The transmission input shaft is being driven by the clutch disk at exactly the same rpm as the crankshaft so the inner race of the pilot bearing (attached to the pilot shaft) turns at the same rpm as the outer race (attached to the crankshaft/flyheel) - the bearing turns as a whole - like the throwout bearing, a defective pilot bearing will only make noise when the clutch is disengaged (pedal down)
what is yellow metal friendly? what type of oil is recommended?
GL5 oils are intended for use in hypoid transmissions where there is a combination of extreme pressure coupled with a sliding/wiping action - early GL5 oils used sulphur as an additive, and under certain temperature & pressure conditions sulphuric acid forms and this destroys the soft bronze synchro rings. Later GL5 oils do not have sulphur and are safe for use with copper and it's alloys (bronze is an alloy of copper and brass, both of which are yellow in color) hence the term yellow metal friendly.
GL4 oils are safe for use in transmissions with bronze, and so are "yellow metal friendly" GL5 oils.