I have a 2000 ls 4x4.The problem im having is the transmission is not shifting.Can shift manually 1st and 2nd smoothly,but wont shift into 3rd or higher.Had a short in the fuel pump 4 wire lead.When i fixed that the transmission started acting up.Everything was fine before the wires shorted out.What do I need to check please

 

**Moved to Engine & Transmission**