Hey Yota Tech, perhaps you can help me out with a transmission/clutch diagnosis.

87 4runner 22re 5speed - ~280,000 miles, all original parts I believe

I have been driving this runner for several years now and it has been a solid rig. Just this last summer 4th gear started crapping out - it would work fine for a period of time and then slip out of gear at which point it would not re-engage and instead make a horrendous grinding sound (at which point i was a 3rd to 5th shifter and the highway drivers hate me). This problem is not persistent and often if I keep my hand on the shifter and don't let it slip out of gear and then the problem never arises.

NOW - One morning i get into the vehicle and crank it up and, after 15 seconds of idling, a *scratchy* Whirring sound begins. Depress the clutch - Gone. Engage into gear and upon moderate acceleration the Whirring returns once above ~2,000 rpm (all gears). Back off of the accelerator slightly and the noise is gone, but the moment I am back on the accelerator it comes back.

VIDEO OF THE NOSIE AT IDLE
It seems like a clutch related issue to me (based on it going away when engaging the clutch pedal), but it seems odd that it was such a quick onset with no provocation that I am aware of. What are your thoughts? Is it possible there is a bearing that needs to be lubricated which is making the noise?

Thanks y'all

 

Sounds like input shaft bearing to me.

 

Here is a video of the noise - its definitely a rattling sound at idle