Have put on a new auto trans every gear selection works perfectly, but 3rd gear. I f I put it in Drive the car will move smoothly from 1st to 2nd then all of a sudden the car just revs high as if in neutral, gearbox is gauranteed that it is good. Could the problem be from installation? The old trans was running fine only reason for change is seals kept poppin out. Wot do you reckon bro?