One problem related to engine grinding noise has been reported for the 2003 BMW 745. The most recently reported issues are listed below.
11/09 driverside window regulator replaced;constantly replacing driver side turn signal bulb; in approx. March 2010 car would randomly not go into reverse and when I was able to get it into drive car would feel sluggish or when coming to a stop felt as if I was hit from behind or car would go into failsafe mode and I would be unable to accelerate, had diagnosed by BMW was told 10k+ to have tranny replaced ; found a rebuilt tranny and replaced in approx. May 2010; here we are in August 2011 and car again began to not go into reverse and give a failsafe notification; attempted to start car today 8/8 to take to shop; however car would not go into reverse and when it finally indicated it was in reverse; actually went forward began to make a weird grinding noise so I turned it off and there it sits in my driveway leaking what I presume to be transmission fluid unable to be driven. Current mileage 133k.