FDC auto tranny to manual 5-speed?

OK so my transmission is doing the whacky thing of revving in higher gears before settling (sometimes slamming) into gear. Happens most when going up hill and after trans fluid is warm.

Other threads suggest this is a valve body problem.

But some others have suggested instead of replacing for new or rebuilt automatic tranny, to get a manual 5-speed installed. They say cheaper and better in the long run.

Any thoughts on this?

If I go with the swap, any reputable/experienced shops in SoCal area that can do this?

Cheers,

Moon