 We bought our Explorer with 7 years and 80k on it.  I did my research before buying the truck.  I knew there were problems with the transmissions along with a list of other known problems.  Our truck seems to have no transmission issues.  It shifts very smoothly.  Of course, it could have already been replaced.  The one problem that we are having is it loses coolant.  Every few days I have to add water to it. Have not had it diagnosed, but will be soon.  My husband worries that it is going into the engine which will cost some major bucks for an engine rebuild.  At this time we are hoping that is not what it is.  I love my truck.  It rides good, is comfortable, and looks good.