Possible transmission problem - 2005

I have a 2005 Altima with 75000 miles. I'm getting a loud "roaring" noise from front of car. Local mechanic inspected and said he did not believe problem was tires or wheel bearings. Suggested it was some type of transmission problem. Does anyone know of any recurring problems Altimas have with transmission, axles, bearings, etc. which might be explanation for the noise. I'm off to the transmission man but thought it would be good to know if there are known recurring problems of this sort.

My wife has a 2005 2.5L and she started hearing an erratic noise from the engine about 8 months ago. It only happened every so often, almost like a rattling within the engine. She recorded the noise and took it in to Nissan. Apparently they have a problem with some 05 models catalytic converters breaking apart and being sucked up into the engine. They replaced her entire engine for free. Then about a month ago this recall came out for the 2.5L ECM. It seems that at lower speeds the engine stalls and can cause accidents. Well my wife calls me telling me that her car is stalling in traffic, so I call Nissan. They reprogram the ECM (takes about an hour) and it's fine.