[t walgamuth]

I believe the 928s had Mercedes automatic transmissions. When Mercedes built their first automatic in the sixties or seventies they copied the GM hydromatic, so it is possible the 928 was at least half a copy of GM's finest. Of course you probably know that Rolls Royce built an aluminum block version of the chevy 366 and ran a turbo hydromatic for years.

Anyhow, there has always been a lot of copying back and forth when a mfgr comes up with an excellent product.