I have been having some tranny problems sometimes while I am driving down the road in high gears going about 50mph my off light on my overdrive light blinks at me and it starts shifting hard I read the codes and I have P0603 and P1728 and p0603 says it has something to do with my PCM. Also as soon as I turn of the truck and start it again the light stopes blinking any help I would be thankfull

 

P1728 means the trans or torque converter is slipping. It's time to have a professional diagnose it.