1999 Ford Escort w/automatic transmission is making a "growling" noise (not grinding) when driven. It becomes noticeable at about 30 mph and gets louderas the speed increases. I've put the car on stands and ran it in gear trying to track down the noise and I suspect it's related to the drivetrain but I've check the wheel bearings & CV joints and they don't appear to be the problem, it seems to be more towards the transaxle but I can't pinpoint it. Any suggestions? Anyone know of similar problems?