I have a 2000 mustang gt, small v8, I keep the car maintained, now, lately when I drive and get to 40 to 42 mph, the rpms race to 3 thousand before it will shift. I have it checked and rechecked, one guy said the transmission needs to be rebuilt at $1900, the car is in excellent condition, only 141.000 miles. Just don't know what to think, Does anyone have any ideas, any assistance is greatly appreciated. Please don't pick on me to much Im 71. thanks