I have a couple ?'s

Are we talking about a transmission that has had the valve body down recently and done any air checks ? Was it working properly when parked after the work in 89? I ask these because in the mid 80's a buddy built a C 4 and when he was air checking it he applied air to the govenor and it stuck it .Wored fine but just would not shift to 3 rd as you are discribing. Just another learning experiance.