My relatively new transmission shifts erratically. (I now have 25,000 miles on it) The 1st to 2nd shift is always firm but will occasionally bang and bang hard. The 2nd to 3rd will also bang sometimes. By bang I mean lurch/jar the entire truck. The bands were adjusted and the problem went away for about 500 miles. Now it's as bad as always. Any thoughts? Fluid is fresh and full.

 

cant help you with diagnosis but I would take it in before it costs big $$ good luck

 

Is it possible the throttle cable is malfunctioning? The speed sensor or RPM sensor on OD housing could be erratic. The valve body could have a internal failure. the tranny could be well on way to fubarred.