BMW e34 Getrag 260 input shaft rattle

Getrag 260 (p/n 23001221327) from a 1992 BMW e34 535i with aprox 201246 miles. Diagnosis due to significant rattling/knocking after single mass flywheel w/ S38 M5 clutch kit conversion. Transmission is in neutral with new Driven GL4 80w-90 gear oil still in the case. Note, this p/n calls for ATF. Redline D4 ATF was initial used and changed to the GL4 80w-90 gear oil to see if symptoms subsided. They did not.