So my 2008 work van has been very good to me... I bought it a few years ago used with 80,000 miles on it and had the transmission serviced then... recently at 150k I had the transmission serviced again... fluid and filter.... no problems... just past due. What I just discovered is that it now slips in reverse if I'm backing up a hill. Seems fine in forward but will not back up an incline. I'm planning to take it back to my mechanics tomorrow but would not mind advice from the experts here..... I'm hoping it is something simple. 2008 Ford Econoline 250.