what's the purpose of the pilot bushing?

[Chingon]

So why is it there? I can only guess it's there for balancing purposes or to guide the transmission into place (hence pilot).

I'm asking 'cuz when we did my bro's clutch install, the bushing wasn't there and we did not notice any adverse effects prior to this..

So what' the purpose and what kind of ill effects could one expect from missing one?

[brazymstrp]

the input shaft actually sits inside the thing. I'm pretty sure the bushing was in there, just kinda hard to tell if you don't know what to look for.

[C-Kwik]

It prevents deflection if the input shaft sees any side load.