05 BMW X5 4.4i Trans Nightmare

[DeanoBambinoX2]

Hello! This is my first time posting.

I drive an 05 BMW X5, it belonged to my grandma before she passed. Ive taken on what feels like the most intensive pain in the butt vehicle I have ever worked on.

For 2 months, I've chased a transmission gremlin and no luck. I'm hoping someone here can help me!

So far? I've replaced all wheel speed sensors, hubs, full brakes, suspension.

I've done coils, plugs, valve covers, MAF, vacuum lines, BCM, battery, alternator, wiring, steering angle, fluid change, flex plate, torque converter, trans filter, vanos solinoids & motors, fuel system, injectors, valve springs & seats, cam postion and crank sensors, knock sensors.

I've even cleaned all terminals and wiring around my trans mission.

Now! It has no codes and does not display limp mode. Ive scanned with a snap on sollus edge, torn through my diagnostics.

It will run fine! Acceleration will run through all 6 gears, no slip or shift issue. But when i let off and slow down? It retards itself. For one second I'll have full engine power then pulls back and no more power to the point i can barely climb a slight hill.

What is going on?