I recently bought a 2000 Mustang GT Vert 5spd. After buying it i found out what i thought was tire noise was actually the rear differential, so i had that rebuilt and 3.73 gears installed. Before that i had some grinding noise which i thought was associated with the rear diff. I have the noise when i accelerate from a dead stop in 1st gear. It doesn't gind with any other shifts, i have noticed a grinding noise that is similar when i was coming to a stop to part this morning. I know that the noise i am describing is pretty general but any input would help, considering i just spent a bunch of money for labor to have the rear diff done i am hoping this won't be expensive.