Mayra 
2005 Nissan Pathfinder SUV XE 4WD 4dr SUV (4.0L 6cyl 5A)
Transmission Issues...
 I to have a 2005 Pathfinder and like the other reviews on this site, I have had the same problems.  The transmission is slipping and I just had to have a major repair with the coolant and fliud mixing together.  There were no signs of this and suddenly while driving on the highway my car overheated.  I also have the vibration of the car at certain speeds.  It's awful that Nissan will not admit to the issue and resolve it.  I have been telling Nissan (Meadowlands) about the vibrations since I purchased the vehicle and they just think its me.  My mechanic indicated that he has never seen this happen.  He couldn't believe that there were no warning signs either.