[ShadeTreeMech]

Look into having a hydraulic pump that runs off the output shaft and it will work. The only thing you're lacking is a pump running ogg the output shaft.

Years ago, older American autos were designed to be bump started; I read some older shop manuals for recommended speeds required to do just that.

Sadly for most of us, automatics are very enigmatic; I'm just now starting to learn about how the internals work. One time I attempted a bump start with a transmission that had a lock up torque convertor. That was a very expensive sounding grinding sound! It didn't hurt the transmission, but the torque convertor wouldn't correctly lock up afterwards. I had to manually engage it to make it work.

Rolling in neutral engine off? Not likely to hurt anything. But attempting to shift into gear may cause residual pressure to attempt to engage the clutches, but there not be enough pressure to completely do the job.

As creative as you are, you may be able to find an electric pump able to give you the start up pressure required. Otherwise a pump running off the output shaft would be the answer. I believe this to be possible, just not easy. And having the torque convertor unlocked would be advisable.

How'd you make the manumatic work? I can see the possiblity of making an auto shift manually, especially when it is electronically controlled, just not sure how to pull it off.