Drive Shaft seized on the final drive splines

[Grumpy Goat]

I drove out there this morning and had a look. I think the main thing is that none of the splines are badly pitted by rust, either in the end of the driveshaft or on the gearbox output shaft or the final drive input shaft. The tech has yet to clean up the surface rust off any of them.
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Before they do any more, they are waiting for the two other techs to come back from vacation, as they both have contacts at BMW and may be able to get it covered under warranty.

Thanks for the additional photos, Michael. As Lee mentioned, the amount of rust (little) seems to not be enough to cause the seizure, but it had to be that if the tech had to use force to drive the mated pieces apart. It makes me wonder how much lube it got from the factory, especially since the boot was also improperly silicone-sealed.

Shame the tech was not sure if he put the 1/2" hole in the boot or if it had it before - if the latter was the case then that could suggest that was the entry point for the water leading to the rust.

Please do keep us updated with how this is proceeding.