mysterious 3-5 shift problem

[2003mach1]

well about 8 months ago i pulled my cab for a headstud install and egr delete, and every since the very first time i drove it after i put it back together it has acted funny (flaring and slipping) on the 3-5 shift. it never threw any codes it just acted kinda weird. i never was able to determine the problem so i just continued to drive it and figured it would get worse and i would be able to diagnose it. just recently it got really bad and started slipping in reverse and 5th and 6th gear, so i pulled the tranny out and the direct clutches were fried.
i just finished the rebuild and installed a Suncoast upgrade direct solenoid and test drove it, and now it acts exactly the same as it did 8 months ago when i put the cab back on. i've already returned it to stock and disconnected the batteries for a relearn and its the same. i've also checked all the obvious stuff like ground wires and all the other connections. i'm stumped.

oh yeah, its a 2003 model with a 5r110w.

[Rob]

Dang, sorry i cant help ya out.. im stumped also. hopefully a tech will see this and help ya out.

[cartmanea]

There was another post like this recently and they had a bad wire between the PCM and trans. Since you had your cab off, try cleaning and reconnecting all the plugs between the trans and PCM.