700r4 not shifting into overdrive

[phil33875]

i have been fighting with this 700r4 for over 6 months off and on. tranny will not shift into overdrive.. i have used a different case, 3 different valve bodies, different overdrive drums, new spacer plates, etc. this is a tranny out of a 91 chevy, that is built up ALOT. i know everyone keeps telling me to go to a powerglide, but i have way too much money in this to give up.the tranny is non-lockup, with a b&m nonlockup converter. the jack@ss that i paid to do it, keeps blaming on something new every week. this time it was the valve bodies fault, so i ordered a full manual valve body from TCI and i still have the same damn problem. What am i missing? Do i need to run any wires to the tranny?

[SedatedS10]

I cant really say in your case but the last 700r4 that i had lost overdrive due to a seal failure. I do know that overdrive comes from 3rd and 4th together but if there is an o-ring or sealing ring in either of those 2 packs it wont build up enough pressure to have 4th