Transmission or torque converter slipping

[scottgun]

Hi all,

I've got a recently new to me 2012 X5d with 120k miles. This is my first diesel, so I'm unsure if this behavior is normal or what my next steps should be.

I did not notice this behavior during the initial test drive, but it could have been there and I just dont remember it. When accelerating from a stop or low speeds with light throttle, the transmission seems to slip quite a lot, as though the torque converter is not locking up. After 2 or 3 seconds, the torque converter locks up and will accelerate as expected with no slipping between shifts. It's just the initial 2 or 3 seconds, which feels like a lot. It also seems to allow the engine to spin all the way down to idle.

Here is a short video of the behavior.
https://streamable.com/rx2dca

I have tried:

• Replacing fluid and filter (liqui-moly toptec 1800)
• Replacing valve body seals
• Replacing valve body solenoids
• Resetting adaptations

I have not tried the ZIP kit for the valve body yet.

Is this normal on the diesels? Would a ZIP kit or valve body rebuild fix this? Or am I looking at a full rebuild?

Thanks!