Mitubishi Lancer 1990 Automatic - does not advance

Good, I have an automatic lancer 1990, a few days ago I went to leave my son to school in that the alternator's strap was cut, I went more than slow home and I did not recaley, I bought the strap and install it without any problem, I made it walk .. impeccable, but at the time of putting the accelerate and does not advance anything, try with 1 - 2 Back impeccable. I took the cat and put it high and start trying the changes in height and it turns out that if you advance in 1 2 and D, but when you lower it has no strength, the oil level is ok, check the filter of the gearbox is impeccable ... I think it can be the discs of the box or the torque converter, in reality I do not know, some advice .....