Classic/Antique Car Repair: Transmission Troubles, chevy 305, salvage yard

Question
Hi Vern,
I have a 1977 Chevy Nova with a 305 engine and a TH350 transmission. The original transmission was slipping so I removed it and replaced it with a used one from an early 80's GM from a salvage yard. The newer transmission has an electrical plug which I believe has something to do with the torque converter. The salvage yard said this was not important and would not effect the transmission operation if not connected. I installed the transmission it worked fine for a couple of months but now it will not shift out of 1st gear and it always seems to be in first gear even when shifted into park. When in "park" the car will not go forward but it acts like its in gear and the brakes are applied. It seems like the torque converter is always locked up.

Any Suggestions? Thanks, Bill

Answer
Hi Bill:
Any time someone tells you "that wire is not important", don't listen to them. The Chevy 305 and 350 with the TH 350 and later the Turbo 400 trannies, are the best transmission GM has ever built. The sensor wire (that you didn't connect), is the sensor for the tranny over heating, which automatically down shift it into low gear until reset by the sensor relay, which is connected to the ignition. Turning the ignition off and letting the car cool for awhile, will reset it self. Since you don't have that relay switch, you are stuck in low gear.

unfortunately, I don't know how to trick the relay switch into resetting the transmission.If you can find a mechanic to do that, you are good to go until next time.