I don't know if this has happened to anybody else but everytime i but my 6x6 in all wheel drive,it seems to overheat within 2 minutes.Anybody have any ideas?This is the third time this has happened and it is starting to get to me.I just replaced the heating sending unit and also installed a manual swith for the fan and still it heats up.It blows all the anti-freeze out the overflow reservoir.Any info would be greatly appriciated.