I have been having this issue intermittently for a couple years where my truck will start early shifting into 3rd at about 25MPH. Its very annoying. I have fixed the issue by removing the #5 Fuse ( 20 AMP ) and it seems to clear the problem. I don't know if the fuse is getting corroded and not making connection, or am I clearing the memory on a computer? I have recently replaced (2k miles ago) the transducer and I have the good Borg Warner Solenoid - so I think those are both good to go.

Any insight from forum would be greatly appreciated!