how do i fix this

 

What vehicle? Please provide more information.

 

Taking a shot in the dark as you posted this in the Diesel section and will assume you are talking about a 68RFE. This code denotes the torque converter slip is unacceptable. Unfortunately, there is not a one part fixes this code every time. The first thing to do after verifying the code will return in manual 3rd is to drop the pan and check for debris. Should you find debris, other than normal wear, you will need at the very least a Valve Body. This tends to be common as they will cross bleed pressure. I have also ran into more than a few input shaft problems. I wish I could be more specific, but inspection is the only way to be sure.

 

Thank you. I refuse to try to read minds. Lol