Has anyone had problem with Nissan Pathfinder atomatic gearbox. Coolant mixing with

trasmission fluid causing gearbox failure and have you had any satisfaction from Nissan

as we seem to have hit a brick wall.My Pathfinder is a 2005 and has done 70 thousand miles but since i bought it in march 2012 i have only done 6000 miles when gearbox went it started with a shudder and was told it was a wheel bearing at a cost of 511 pounds.I have since found out that there is a problem known in U.S.A by Nissan but denied in this country.