I have just finished building my 2wd cosworth. I bought the car stripped and I have spent 3-4 months restoring it. I got the car running yesterday, but the gearbox was making a loud winning noise. I have checked the gearbox oil and it was empty. Filled it up until the ATF was running out the filler hole. The whinning noise is still there but dissappears when the clutch is depressed. The clutch, bearing etc came out of my other saff and from what I can remember, it wasnt making this noise in there.

The gearbox has sat for around a year. I havent been able to drive the car anywhere yet has it has no mot or tax, and has so far only been idling on my drive.

Is this whinning noise likely to dissapear once I put some miles on it or is it more likely that the bearings are goosed??