2004 6.0L trans issues

I have a 04 6.0 and my transmission is acting funny. Sometimes when I go to accelerate it feels like the parking brake is set and isnt allowing full power. Also hard to accelerate up inclines. While cruising around 55-60 mph transmission will down whift without warning then immediately shift back up. I'm having a lot of vibration when in reverse and it seems like it has a delay when sifting into reverse.

I hate to say it, but it sound like your trans is hurt and gonna need a rebuild.

How much boost are you showing? Engine power problems very often look like a transmission problem but are not. I would check boost and fuel pressure before condemning trans, also get codes read, engine and trans, not all code readers will read Ford trans codes.