TH350 squeal grind screech after fluid change

[scottdburnett]

My 72 C10 sat over the winter and this spring wouldn't shift into gear after starting up. Realized that I must have had enough fluid leak out to prevent shifting.
I jacked it up and drained the fluid, less than a quart, dark and dirty. As recommended by others on 67-72, I had to jack up the tranny a little bit under the flywheel cover to get the bolts behind the crossmemeber, then dropped the pan, cleaned the pan, installed a new filter and gasket. Reinstalled everything w proper bolt torques and added 4 quarts of fluid.
Started it up and there was instant high pitched squeal of grinding metal.

Shut down, cycled through the gears several times and re-started. Sounded better in park but still there was a new squeal, let it run to warm then checked the fluid level. It was a little high so I drained some fluid out.
Now the squeal still present but shifting into reverse or drive intensifies the grinding squeal.

What have I gotten myself into?
Did jacking up the transmission mess with the flywheel?

Sound in Park:
https://youtu.be/8VVPz4CnzZU

Sound when shifting to Reverse:
https://youtu.be/fanyF1P2E_o

[scottdburnett]

Nevermind.... I dropped the flexplate cover and the nose went away... will replace. I learn lots of lessons the hard way.

[geezer#99]

Be careful finding a new cover. There are a couple styles.
Likely better to mod or straighten yours.

[Dead Parrot]

Look for scratch marks on the inside of the cover. Adjust spacing with gentle hammer strikes on cover. Reinstall old cover.

Start with where the jack lifted up on the cover.

[nikwho]

Did you jack the transmission up by the cover?