I was thinking of switching to a synthetic ATF when I change the ATF in my wifes truck down the road. Do I need to drain the torque converter too or would it be alright to just drain the pan?

 

Are you awhere of just how much fluid the converter holds?
It is more than half the total so only doing the pan won't accomplish your goal.
As to mixing, there is no real problem as long as both are the same specified fluid such as Mercon V "or whatever type your transmission is supposed to have".

 

Thanks, I read the other threads and came to that conclusion. I want to try to do this myself as it needs to be done fairly often in these trucks.