This is my first post so hello to everyone.
First thing first i own 2002 Mitsubishi Lancer es 5Spd m/t FWD(obv).
To start I have replace the Throwout bearing and the Clutch TWICE as per local shops in my area (Sacramento). I have also replaced the motor with the same engine as before only a Japanese version with 30k on it due to a belt slip that threw a rod. but that is not the problem.
The problem is that my transmission sounds like it has marbles in it or something.
At idle with clutch in the car makes zero noise.
At idle with clutch depressed the car makes a rattling noise(similar to throwout bearing noise)
Taking off in first from a dead stop is when the car makes the worst noise( marbles/metal on metal high pitch chirping and grinding) BUT ONLY UNTIL ABOUT 3,000 RPM!
From first to second while in the process of shifting (depressing the clutch and pressing gas) ther is the same noise but slightly muffled until about 2,500RPM
in third the noise is very faint and happens intermittently.
In Fourth, Fifth and Reverse the noise is gone.

when shifting and or pressing and depressing clutch and moving from gear to gear everything is flawlessly smooth!
now the problem is i dont want to spend anymore money until i get a FOR SURE DIAGNOSIS!
i have heard from a number of people that the trans is bad, but i drive this car 12.8 miles 4 days a week to work and back and let me tell you everything about shifting is perfect, no grinding, no nothing. but if im taking off from a dead stop the noise is just so profound i cannot stand it.

I work at a Toyota dealership where i live and have worked on cars myself before. when i took the vehicle to the guy who i know, who knows Mitsubishi and Evo's (being that he owns and customized one) He is telling me that i need to replace the Input Shaft Bearing and a few seals in the trans.

Honestly i dont care which i have to replace the trans or the input shaft bearing i just need to know for sure. I'm tired of spending money on stuff when i could be buying shocks, spring ans sway bars and struts to make my car handle like a dream.
Sorry for the long post I just figured the more details i include in this post the more likely i am going to get a straight forward honest answer.

P.S. if you have had this problem before what steps did you take to find the problem and how is that vehicle running now?

 

food for thought...

i just rebuilt my evo transmission, granted not the same but close. the input shaft bearings require a press and clip pliers to remove. on top of that when you reinstall them you have to reassemble the transmission several times to setup up the shims and bearing end play.

this means time... lots of it. not to mention pulling and reinstalling the trans. more time.

or you can buy a rebuilt unit, with a warranty, and just remove and install.. less time and no more worries.
and this is only if he is right. my friends evo made similar noises as what you described and his gear teeth sheered off... he bought a used unit off of here for 800.

i will suggest that you at a minimum swap the clutch disc and tob while its all out to save time and money in the future. also have the flywheel/pressure plates machined to suit.

 

I was thinking the same thing but im not a huge transmission guy nor do i wanna pay someone for all of those hours. Reading it definitely puts it in perspective. Appreciate the well put answer sir.