Box 4x4 Automatic Ford Explorer 96

Good evening to everyone, who can help me: I would like to know if any of you has knowledge about 4x4 Explorer automatic boxes, I have a fault and take it to the mechanic I put the scanner and tell me that you have to change the box, that the turbine is not working well and that it is better to not have problems than the turbine damages the box to change everything does not repair it but to change the entire box, but I have doubt about it. Applying the Dray, but the rest is fine, it has strength in start and changes well the only thing is that it takes about 5 or 6 seconds to apply the Dray. Help me please