TH400 won't reliably go into passing gear...

[Firebirdjones]

Good to hear.

That kickdown system has alot more to do with the trans than just passing gear. It also increases line pressures, (I forget to which clutch pack assembly) (direct I think) Been a while since I've had one torn down. But it can cause internal damage over long term if not functioning properly. So that's another good reason to have a functional downshifting system.