Noise occurred occasionally (sic) for a few seconds at low speed - basically sounded like I had run over a piece of metal and it banged up underneath the car - then immediately went away. This happened a few times then once again at parking lot speed - slowed to crawl, shifted into N then back to Drive and it went away. Parked, drove home later and all was well. I THOUGHT FOR SURE THE A-DRUM HAD SELF-DESTRUCTED! Otherwise, shifting et al was 100% - no code faults - mystified. Anyway, the next step was a call to the dealer (no fun whatsoever) and they said tow it in and we'll charge you a grand to check it out, so instead we (neighbour and I - Sask. farmer - they fix enything!) took a slow test drive. Major grinding noise from right rear wheel area. Question - could this all be related to a wheel bearing? Inner tread on rear tires show considerable wear. Some variable vibrations but at odd speeds.
I would greatly apprciate feedback as well as any info about DIY wheel bearing replacement (I'd buy the large socket to remove the nut bt I don't have a hydraulic press). I really hate what dealers charge for poor information. In this case they never even suggested that the problem may be bearing - they immediately said ZF problem.

Larry - Calgary, Ab
2002 XJ8 Sport, 136,000km
1994 850 Turbo MINT!
2008 Saturn Arua XR