I have a 1995 3.4L automatic. It seems that when I accelerate hard in first gear and between first and second gear, it feels like I am spinning wheels, but I know thats not the case. If I accelerate over 4000rpms (give or take), the engine continues to rev up but no power is going ot the ground and I hear what sounds to be almost a grinding noise coming from the rear. Does anyone know what the problem could possibly be?