Can't figure out what this noise is coming from

Well, for a while I have been hearing a noise, but only recently is it getting louder.
In the morning, or whenever the engine's cold, when i start the car and put it into gear, i always hear a kind of grinding noise, or like there's something loose up under the engine making a rattling noise. I have no idea, but i'm guessing it's something to do with the trans. only because it makes the noise only when in gear. Also, once the car gets warmed up (driven for like 2 min.) the noise goes away and I don't hear it for the rest of the day.
Please let me know if you have any thoughts as to what it could be. Thanks.

Had the same problem in my car. Look for a post called T-5 tranny question. A few guys gave me the best explanations on what exactly it was. Something about the wrong grease being used. I know a guy that works on T-5's all day cause they use to be in mustangs (and unfortuantly he works on them) but he says its just a Borg and Wagner thing. A lot of guys have had the same problem with the T-56.

but check out that post it should clear things up. It makes sense cause if you let the car warm up it doesn't do it