bootmaker 9/30/2012This is a common Problem and it can be serious needing a full rebuild. If your lucky it may only be a shift/ coast solenoid 7G484. There are four of them in your transmission. To change the solenoid you will need to drop the transmission pan and remove the filter. If there is a lot of metal sludge and chunks of metal you will probably need a full rebuild. Take it to a shop. If you do it your self you will need a ATSG Ford 5R55E manual. You can buy one at ford or spend less and search for one on eBay. The parts are also cheaper on eBay. You will want to change all the fluid in your transmission and power booster. Use fluid Mercon V only.
gearbox 9/30/2012usually it's a sign the computer sees something wrong with the transmission and needs to be scanned to diagnose . I wouldn't replace parts till you know the code as it can also set for stuff outside the transmission.
5r55 tech 10/1/2012What code was in memory