gear grinding

okay, i mentioned this earlier, but i have more info on the problem.

I mentioned that i was hearing a noise when i was in first gear and accelerating. I noticed that it usually only happen when i came to a complete stop, went into first, and began to accelerate. I have been able to narrow down the problem and reproduce it consistantly now.

It happens, I think in any gear, when my RPMs are at around 1,000. As soon as i roll past a little more then 1k rpm, i hear the noise. So what i do to replicate it is get into first gear, drive and then slowly slow down till my rpms are at 1k or a tad lower, and then begin to accelerate and it happens.

My car is a 1994 Mustang GT convertible.

Anyone have any ideas why this is happening or what could cuase this? I would like to have some idea before i take it into a mechanic to get looked at.
Thanks in advance for your help.

is it a constant grind or more of a quick metal to metal contact your hearing? it may just be gear lash. im assuming this is a 5 spd. have you checked to see if you where low on fluid? 1000rpms may just be where you can hear it. and are you sure its your transmission?

sounds more like a quick thing, it only lasts maybe a second or two. I had the car taken in just last week where they checked all the fluid. I am away from my car right now so when I get back home tommorow I will check it myself.
It is a 5spd. It is true that 1000 may just be where i hear it, but it ins't like the sound fades away, it just stops after you get up to like 1,400 or 1,500, around there.
I am not sure it is my tranmission, I really have no idea what it could be, since I can only replicate it when i am in the car, so i can't get out to see what is happening or where it is coming from.

im thinking that it may just not be loud enough to be heard at higher rpms. while your under the car check your rearend fluid. if its low just fill it up enought to where you can feel the fluid with your finger below the filler hole. your rearend takes 90 weight gear oil. it may not be gears at all, if its a growl you may have bearing problems. check your u-joints too, they may be loose which you could be hearing them ride on the bolts. doubtfull though. probably tranny or rearend.