Hello all,
my van has been making a high pitched whining sound for a few weeks and thought it was mostly electrical. It gets louder when you accelerate. Earlier this week when trying to take my son to school, my transmission slipped and seemed to have trouble going up a hill. Not taking a chance, took it right back home and used another vehicle for the school drop off. I parked the van back in my drive and left it for the time being. That happened on Thursday. Today, I put some Lucas transmission fluid in the tranny to see if it help. I was about to take it for test drive, when now it won't seem to go into any gear, I can't feel it engage and any gear I try to put it in, the shift indicator flashes and go to 'R'(reverse).

 

Transmission may have gone into limp in. Is the check engine lamp on? If it is I would have the van checked for codes. That noise you heard may have been the planetary gear coming apart.