MNSmith: back in the early days of the 700R4, like thru 87, the output shaft of that trans had two holes drilled in it to locate the retaining clip for the speedo drive gear. Corvette was the only odd-ball, having a specific extension housing which used the rearward locating hole, meaning the positioning of the driven gear in the extension housing was different also. You said Corvette 1986, but does it really have a Corvette extension housing? Does the output shaft have one or two holes drilled back there for the drive gear? Was the output shaft maybe changed out for one with a single hole? You can mix and match a lot of parts in that tranny, but it doesn’t always work out. Sounds like the drive and driven gear aren’t lined up correctly. Just a few things to consider. Good luck, Dave
