torque converter ?
 

what are the symptoms of a faulty torque converter lock up switch.

Anybody got any ido on this

I think your truck would hesitate before moving if you had a problem with the torque converter not to mention you can feel when your tc locksup or comes out of that mode.
What symtoms do you have?

at first it would drop in and out ofoverdrive now it wont go into overdrive it shifts into the rest of the gears fine fluid is fine im trying to eliminate everything besides the tranny

I would change the 1st and 2cnd gear shift cylinoids.Could also be the actuator piston thats on the side of the trans.What is the fluid like red or dirty.

torque converter lockup failure will not be felt if it is stuck unlocked. it occurs in overdrive. if stuck locked it will stall your truck. When solenoids fail you get either 1st and 4th gear only or 2nd and 3rd gear only. If your only missing 4th you can try changing your filter but It's most likely your trans is on its way out

I think if you read up on this there are sveral write ups on the forum,by doing a search you will find them.