Does a 2005 Nissan Altima 2.5SL have a constant variable transmission?

Nissan Altima 2.5L 2005 - Humming noise?

• I have Nissan Altima 2.5L 2005. It drives well, but when it got to speed of 50-55 mph or more. I start hearing a slight humming noise. I brought it to Nissan and they told me that the transmission and everything is fine (spent $79 bucks or so for diagnosis). Also, not sure if this is related, but when I turn on AC in "D" drive mode, I can hear loud and sharp noise occasionally when I'm stopping, the sharp noise goes away after I hit gas pedal. At the dealership, I insist that this problem occurs, so they checked again and told me that the front motor mount is slightly bent and that it would cost me $550 bucks to fix that. I'm a little skeptical if fixing this might solve the problem.....well, I'm screwed if I spend $550 bucks and still have the same problem So, if anyone has experience on this, please give me an advice.

• Answer:

  sounds like a tire problem. usually if you have a noise at certain speeds its tire related. bearinig noise would be at all speeds and change the harmonics at diff speeds. take your car to a tire shop that uses a Road Force balancer. they can check each tire to determine which one either has a seperated belt or is to high on the road force reading. good road force will be less then 12 if higher then 12 is bad. I think they may tell you the limit is 15 or higher but I have found 12 and under the best.