700R4-4L60 Techie Question

[beanious]

Hello all, I've noticed on two of my trucks that have 4L60-700R4s, that when they're in neutral and the wheels are off the ground the tires spin at about 10 miles an hour.

I'm wondering what causes this, I'm assuming it's due to either friction from rotating internals or fluid inertia transferred to the output shaft.

Also if anyone has any ideas on how to eliminate the output shaft spin in neutral and get a true neutral, that would be a huge win. I've been thinking that a 2-4 band apply when in neutral might eliminate the unwanted output shaft rotation, no clutches are applied in neutral so I don't think there would be any drive gears engaged. I have an NP205 behind one of the 4L60-700R4s and it hates input-output shaft speed variance, I've started shifting it at 10 mph as a work around but it would be nice to shift in neutral while stopped.

Thanks in advance.