I re & re'd my engine to do a colour change on my truck. The only thing I did was put a new seal in the transmission before I put theTC back in.I did not drain the TQ. I dropped the pan & replaced the filter. Added fluid. There process was over several months. Now the truck will not shift into drive or OD. If I play with the shifer while driving it some times well go into drive. The shifts fell like they are hanging up. I now have a service engine lite as well. If seems to shift 1st to 2nd OK. Any ideas??????

 

First, find out what the code is from the CEL. (turn key on,off,on,off,on and the code will display in the odometer) Then see where that leads you.