The 3 speed plus overdrive tranny wont shift into overdrive all the time. Will shift when engine is cold at 55-60. but when warm- 80+ or never. Anyone know what the problem could be?

i may be wrong but think the overdrive is in the torque convertor, or so im told

o, to be honest i know cars but i dont know a whole lot. So are you saying my torgue converter is out then?

You must have a th700r4 tranny... It's not your torque converter as stated it is a problem in the computer that shifts the tranny.. As in a relay..

does that mean i need a new computer

the computer does not control transmission shifting just torque converter lockup.could be a valvebody problem, tv cable adjustment or 3-4 clutch pack going out in the transmission