mustang v auto its my first car and maintenance has all been kept up with really no problems i bought it with k miles the alternator went out around k and i fixed that no problems now im at k miles and once i start to cruise around mph i hear a loud grinding noise whenever im accelerating there is no grinding whatsoever now i reach and cruise at kish rpm and it sounds like gears grinding it started about weeks ago im pretty into cars and im saving for a cls but i cant quite afford it yet so i need to get this fixed asap and any help is much appreciated i can do a lot of work if i have to by myself but if i have to replace the tranny or something then i just dont have time as im working near hrs a week