My transmission is making whirring noises like a bad bearing. It happens specifically in 1st gear above 1k rpms. It shifts/acts fine, it just makes noise.
I just changed the clutch, pressure plate, throwout bearing and pilot bearing, did not make it go away. I was wondering what it could be, the main shaft bearing or the differential bearing? Should i go get a used one or is it cheap enough to get a rebuild kit for my transmission?

 

Get a used trans, the cheapest way to go, otherwise it sounds like first speed gear bearing is gone if it's only happening in first.

 

If it's more noticeable in 1st, less so in 2nd (sometimes have to be in a quiet area, and get the revs up) and can't make it out at all in 3rd-5th, I thought that could also be the mainshaft bearing. I don't really know, but I've read that.
(edit: Just so we're clear, I'm talking when you leave it in gear and have the car rolling but the clutch is disengaged, to the floor. Getting the revs up in said gear, then only when you put the clutch in can you hear it. If you are hearing a bearing noise from the trans. over the sound of the engine while driving, with clutch engaged, that would be a much louder noise and more serious issue.)

Mine's the same way ('92 EX) for what it's worth, been like that since I got it and doesn't seem to have gotten any worse.

If you have it at idle, in neutral, and you let the clutch pedal up, do you hear a noise as soon as you start to engage the clutch? If so, I believe that's the mainshaft bearing you are hearing. Most used cars w/ manuals I've been in make that noise (most of which have been Hondas), at least when I've bothered to check for it.

I can't say for sure the sound at idle w/ clutch engaged is the same thing causing the noise in 1st, but possibly.

 

Exactly what it is... i think im just gonna tell people who ask that i have a dog-toothed racing tranney

 

I would just take it to Amco or something and have them computer diagnose it and thats it. They do it for FREE!