Okay so i bought my 90 mustang 4 years ago it is a automatic a week after i bought it the tranny took a poo on me lost reverse so i had it rebuilt fast forward to present and now when i drive in o/d after it shifts through first second and third gets to where it should shift in to o/d at about 2500 - 2000 rpm it wont shift but it wont accelerate it will just rev like its in neutral but once it drops back down to below the shift point i have power again so i dont know if its an electrical or mechanical issue any help is appreciated