It depends. If there's no work and you bring it at 8 am and we have all the parts we can have it done by lunch time. Call ahead and let us know and we'll give you a more approximate estimate.
A transmission already makes plenty of noise but some noises like whining or grinding is something to worry about. It can be something as simple as a bearing or something like a broken tooth on a gear. Bring it in and we'll tell you exactly what it is.
When you press the clutch you disengage it from the transmission. So if it makes a noise while it's connected then usually there's something inside of the transmission that makes the noise. But, it could be something like a faulty clutch that's rattling from the springs or the throwout bearing.
This all depends on what kind of transmission it is. Trans-axles (Front wheel drives) tend to be a little more expensive because of the work that's needed to be done like basically dismantling the whole front end. Transmissions (Rear wheel drives) are cheaper compared to the trans-axles because there's less of us turning wrenches involved.
You'd be surprised what fluids these transmissions take. Most people who come in still think they have to put 90 W in their transmission but modern transmissions will fail because of this. Most transmissions now use A.T.F (Automatic Transmission Fluid) or 30 W motor oil. Always call us and ask and don't listen to the guy at the parts store who says it takes 90 W because he's not the one who's going to warranty the work.
Give us a call. We are all humans and make mistakes and it's rare for us not to take a customers information down but you'd be surprised how many people leave their transmission with us and try to take off without giving us their info.